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commit 428080c9b19bfda37c478cd626dbd3851db1aff9 upstream.
In preparation for implementing rigorous build time checks to enforce
that only code that can support it will be called from the early 1:1
mapping of memory, move SEV init code that is called in this manner to
the .head.text section.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240227151907.387873-19-ardb+git@google.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 48204aba801f1b512b3abed10b8e1a63e03f3dd1 upstream.
The .head.text section is the initial primary entrypoint of the core
kernel, and is entered with the CPU executing from a 1:1 mapping of
memory. Such code must never access global variables using absolute
references, as these are based on the kernel virtual mapping which is
not active yet at this point.
Given that the SME startup code is also called from this early execution
context, move it into .head.text as well. This will allow more thorough
build time checks in the future to ensure that early startup code only
uses RIP-relative references to global variables.
Also replace some occurrences of __pa_symbol() [which relies on the
compiler generating an absolute reference, which is not guaranteed] and
an open coded RIP-relative access with RIP_REL_REF().
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240227151907.387873-18-ardb+git@google.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d2a285d65bfde3218fd0c3b88794d0135ced680b upstream.
Move the __head section definition to a header to widen its use.
An upcoming patch will mark the code as __head in mem_encrypt_identity.c too.
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/0583f57977be184689c373fe540cbd7d85ca2047.1697525407.git.houwenlong.hwl@antgroup.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit bebb5af001dc6cb4f505bb21c4d5e2efbdc112e2 which is
commit f2208aa12c27bfada3c15c550c03ca81d42dcac2 upstream.
It is reported to cause problems in the stable branches, so revert it.
Link: https://lore.kernel.org/r/899b7c1419a064a2b721b78eade06659@stwm.de
Reported-by: Wolfgang Walter <linux@stwm.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 312be9fc2234c8acfb8148a9f4c358b70d358dee upstream.
The MSR_PEBS_DATA_CFG MSR register is used to configure which data groups
should be generated into a PEBS record, and it's shared among all counters.
If there are different configurations among counters, perf combines all the
configurations.
The first perf command as below requires a complete PEBS record
(including memory info, GPRs, XMMs, and LBRs). The second perf command
only requires a basic group. However, after the second perf command is
running, the MSR_PEBS_DATA_CFG register is cleared. Only a basic group is
generated in a PEBS record, which is wrong. The required information
for the first perf command is missed.
$ perf record --intr-regs=AX,SP,XMM0 -a -C 8 -b -W -d -c 100000003 -o /dev/null -e cpu/event=0xd0,umask=0x81/upp &
$ sleep 5
$ perf record --per-thread -c 1 -e cycles:pp --no-timestamp --no-tid taskset -c 8 ./noploop 1000
The first PEBS event is a system-wide PEBS event. The second PEBS event
is a per-thread event. When the thread is scheduled out, the
intel_pmu_pebs_del() function is invoked to update the PEBS state.
Since the system-wide event is still available, the cpuc->n_pebs is 1.
The cpuc->pebs_data_cfg is cleared. The data configuration for the
system-wide PEBS event is lost.
The (cpuc->n_pebs == 1) check was introduced in commit:
b6a32f023fcc ("perf/x86: Fix PEBS threshold initialization")
At that time, it indeed didn't hurt whether the state was updated
during the removal, because only the threshold is updated.
The calculation of the threshold takes the last PEBS event into
account.
However, since commit:
b752ea0c28e3 ("perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG")
we delay the threshold update, and clear the PEBS data config, which triggers
the bug.
The PEBS data config update scope should not be shrunk during removal.
[ mingo: Improved the changelog & comments. ]
Fixes: b752ea0c28e3 ("perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG")
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240401133320.703971-1-kan.liang@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 99485c4c026f024e7cb82da84c7951dbe3deb584 upstream.
There are few uses of CoCo that don't rely on working cryptography and
hence a working RNG. Unfortunately, the CoCo threat model means that the
VM host cannot be trusted and may actively work against guests to
extract secrets or manipulate computation. Since a malicious host can
modify or observe nearly all inputs to guests, the only remaining source
of entropy for CoCo guests is RDRAND.
If RDRAND is broken -- due to CPU hardware fault -- the RNG as a whole
is meant to gracefully continue on gathering entropy from other sources,
but since there aren't other sources on CoCo, this is catastrophic.
This is mostly a concern at boot time when initially seeding the RNG, as
after that the consequences of a broken RDRAND are much more
theoretical.
So, try at boot to seed the RNG using 256 bits of RDRAND output. If this
fails, panic(). This will also trigger if the system is booted without
RDRAND, as RDRAND is essential for a safe CoCo boot.
Add this deliberately to be "just a CoCo x86 driver feature" and not
part of the RNG itself. Many device drivers and platforms have some
desire to contribute something to the RNG, and add_device_randomness()
is specifically meant for this purpose.
Any driver can call it with seed data of any quality, or even garbage
quality, and it can only possibly make the quality of the RNG better or
have no effect, but can never make it worse.
Rather than trying to build something into the core of the RNG, consider
the particular CoCo issue just a CoCo issue, and therefore separate it
all out into driver (well, arch/platform) code.
[ bp: Massage commit message. ]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Elena Reshetova <elena.reshetova@intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240326160735.73531-1-Jason@zx2c4.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3ddf944b32f88741c303f0b21459dbb3872b8bc5 upstream.
Modifying a MCA bank's MCA_CTL bits which control which error types to
be reported is done over
/sys/devices/system/machinecheck/
├── machinecheck0
│ ├── bank0
│ ├── bank1
│ ├── bank10
│ ├── bank11
...
sysfs nodes by writing the new bit mask of events to enable.
When the write is accepted, the kernel deletes all current timers and
reinits all banks.
Doing that in parallel can lead to initializing a timer which is already
armed and in the timer wheel, i.e., in use already:
ODEBUG: init active (active state 0) object: ffff888063a28000 object
type: timer_list hint: mce_timer_fn+0x0/0x240 arch/x86/kernel/cpu/mce/core.c:2642
WARNING: CPU: 0 PID: 8120 at lib/debugobjects.c:514
debug_print_object+0x1a0/0x2a0 lib/debugobjects.c:514
Fix that by grabbing the sysfs mutex as the rest of the MCA sysfs code
does.
Reported by: Yue Sun <samsun1006219@gmail.com>
Reported by: xingwei lee <xrivendell7@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/CAEkJfYNiENwQY8yV1LYJ9LjJs%2Bx_-PqMv98gKig55=2vbzffRw@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 04c35ab3bdae7fefbd7c7a7355f29fa03a035221 upstream.
PAT handling won't do the right thing in COW mappings: the first PTE (or,
in fact, all PTEs) can be replaced during write faults to point at anon
folios. Reliably recovering the correct PFN and cachemode using
follow_phys() from PTEs will not work in COW mappings.
Using follow_phys(), we might just get the address+protection of the anon
folio (which is very wrong), or fail on swap/nonswap entries, failing
follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and
track_pfn_copy(), not properly calling free_pfn_range().
In free_pfn_range(), we either wouldn't call memtype_free() or would call
it with the wrong range, possibly leaking memory.
To fix that, let's update follow_phys() to refuse returning anon folios,
and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings
if we run into that.
We will now properly handle untrack_pfn() with COW mappings, where we
don't need the cachemode. We'll have to fail fork()->track_pfn_copy() if
the first page was replaced by an anon folio, though: we'd have to store
the cachemode in the VMA to make this work, likely growing the VMA size.
For now, lets keep it simple and let track_pfn_copy() just fail in that
case: it would have failed in the past with swap/nonswap entries already,
and it would have done the wrong thing with anon folios.
Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():
<--- C reproducer --->
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <liburing.h>
int main(void)
{
struct io_uring_params p = {};
int ring_fd;
size_t size;
char *map;
ring_fd = io_uring_setup(1, &p);
if (ring_fd < 0) {
perror("io_uring_setup");
return 1;
}
size = p.sq_off.array + p.sq_entries * sizeof(unsigned);
/* Map the submission queue ring MAP_PRIVATE */
map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
ring_fd, IORING_OFF_SQ_RING);
if (map == MAP_FAILED) {
perror("mmap");
return 1;
}
/* We have at least one page. Let's COW it. */
*map = 0;
pause();
return 0;
}
<--- C reproducer --->
On a system with 16 GiB RAM and swap configured:
# ./iouring &
# memhog 16G
# killall iouring
[ 301.552930] ------------[ cut here ]------------
[ 301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100
[ 301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g
[ 301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1
[ 301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4
[ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100
[ 301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000
[ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282
[ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047
[ 301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200
[ 301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000
[ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000
[ 301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000
[ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000
[ 301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0
[ 301.565725] PKRU: 55555554
[ 301.565944] Call Trace:
[ 301.566148] <TASK>
[ 301.566325] ? untrack_pfn+0xf4/0x100
[ 301.566618] ? __warn+0x81/0x130
[ 301.566876] ? untrack_pfn+0xf4/0x100
[ 301.567163] ? report_bug+0x171/0x1a0
[ 301.567466] ? handle_bug+0x3c/0x80
[ 301.567743] ? exc_invalid_op+0x17/0x70
[ 301.568038] ? asm_exc_invalid_op+0x1a/0x20
[ 301.568363] ? untrack_pfn+0xf4/0x100
[ 301.568660] ? untrack_pfn+0x65/0x100
[ 301.568947] unmap_single_vma+0xa6/0xe0
[ 301.569247] unmap_vmas+0xb5/0x190
[ 301.569532] exit_mmap+0xec/0x340
[ 301.569801] __mmput+0x3e/0x130
[ 301.570051] do_exit+0x305/0xaf0
...
Link: https://lkml.kernel.org/r/20240403212131.929421-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Wupeng Ma <mawupeng1@huawei.com>
Closes: https://lkml.kernel.org/r/20240227122814.3781907-1-mawupeng1@huawei.com
Fixes: b1a86e15dc03 ("x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn vma routines")
Fixes: 5899329b1910 ("x86: PAT: implement track/untrack of pfnmap regions for x86 - v3")
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b377c66ae3509ccea596512d6afb4777711c4870 upstream.
srso_alias_untrain_ret() is special code, even if it is a dummy
which is called in the !SRSO case, so annotate it like its real
counterpart, to address the following objtool splat:
vmlinux.o: warning: objtool: .export_symbol+0x2b290: data relocation to !ENDBR: srso_alias_untrain_ret+0x0
Fixes: 4535e1a4174c ("x86/bugs: Fix the SRSO mitigation on Zen3/4")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240405144637.17908-1-bp@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 0aa6b90ef9d75b4bd7b6d106d85f2a3437697f91 ]
Some BIOSes allow the end user to set the minimum SEV ASID value
(CPUID 0x8000001F_EDX) to be greater than the maximum number of
encrypted guests, or maximum SEV ASID value (CPUID 0x8000001F_ECX)
in order to dedicate all the SEV ASIDs to SEV-ES or SEV-SNP.
The SEV support, as coded, does not handle the case where the minimum
SEV ASID value can be greater than the maximum SEV ASID value.
As a result, the following confusing message is issued:
[ 30.715724] kvm_amd: SEV enabled (ASIDs 1007 - 1006)
Fix the support to properly handle this case.
Fixes: 916391a2d1dc ("KVM: SVM: Add support for SEV-ES capability in KVM")
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Cc: stable@vger.kernel.org
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240104190520.62510-1-Ashish.Kalra@amd.com
Link: https://lore.kernel.org/r/20240131235609.4161407-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 466eec4a22a76c462781bf6d45cb02cbedf21a61 ]
Convert all local ASID variables and parameters throughout the SEV code
from signed integers to unsigned integers. As ASIDs are fundamentally
unsigned values, and the global min/max variables are appropriately
unsigned integers, too.
Functionally, this is a glorified nop as KVM guarantees min_sev_asid is
non-zero, and no CPU supports -1u as the _only_ asid, i.e. the signed vs.
unsigned goof won't cause problems in practice.
Opportunistically use sev_get_asid() in sev_flush_encrypted_page() instead
of open coding an equivalent.
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240131235609.4161407-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Stable-dep-of: 0aa6b90ef9d7 ("KVM: SVM: Add support for allowing zero SEV ASIDs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 0e110732473e14d6520e49d75d2c88ef7d46fe67 upstream.
The srso_alias_untrain_ret() dummy thunk in the !CONFIG_MITIGATION_SRSO
case is there only for the altenative in CALL_UNTRAIN_RET to have
a symbol to resolve.
However, testing with kernels which don't have CONFIG_MITIGATION_SRSO
enabled, leads to the warning in patch_return() to fire:
missing return thunk: srso_alias_untrain_ret+0x0/0x10-0x0: eb 0e 66 66 2e
WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:826 apply_returns (arch/x86/kernel/alternative.c:826
Put in a plain "ret" there so that gcc doesn't put a return thunk in
in its place which special and gets checked.
In addition:
ERROR: modpost: "srso_alias_untrain_ret" [arch/x86/kvm/kvm-amd.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:145: Module.symvers] Chyba 1
make[1]: *** [/usr/src/linux-6.8.3/Makefile:1873: modpost] Chyba 2
make: *** [Makefile:240: __sub-make] Chyba 2
since !SRSO builds would use the dummy return thunk as reported by
petr.pisar@atlas.cz, https://bugzilla.kernel.org/show_bug.cgi?id=218679.
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404020901.da75a60f-oliver.sang@intel.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/202404020901.da75a60f-oliver.sang@intel.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit 4535e1a4174c4111d92c5a9a21e542d232e0fcaa upstream.
The original version of the mitigation would patch in the calls to the
untraining routines directly. That is, the alternative() in UNTRAIN_RET
will patch in the CALL to srso_alias_untrain_ret() directly.
However, even if commit e7c25c441e9e ("x86/cpu: Cleanup the untrain
mess") meant well in trying to clean up the situation, due to micro-
architectural reasons, the untraining routine srso_alias_untrain_ret()
must be the target of a CALL instruction and not of a JMP instruction as
it is done now.
Reshuffle the alternative macros to accomplish that.
Fixes: e7c25c441e9e ("x86/cpu: Cleanup the untrain mess")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit e8efc0800b8b5045ba8c0d1256bfbb47e92e192a upstream.
Factor out the UNTRAIN_RET[_*] common bits into a helper macro.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/f06d45489778bd49623297af2a983eea09067a74.1693889988.git.jpoimboe@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit 34a3cae7474c6e6f4a85aad4a7b8191b8b35cdcd upstream.
CONFIG_RETHUNK, CONFIG_CPU_UNRET_ENTRY and CONFIG_CPU_SRSO are all
tangled up. De-spaghettify the code a bit.
Some of the rethunk-related code has been shuffled around within the
'.text..__x86.return_thunk' section, but otherwise there are no
functional changes. srso_alias_untrain_ret() and srso_alias_safe_ret()
((which are very address-sensitive) haven't moved.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/2845084ed303d8384905db3b87b77693945302b4.1693889988.git.jpoimboe@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit aa730cff0c26244e88066b5b461a9f5fbac13823 upstream.
Move srso_alias_return_thunk() to the same section as
srso_alias_safe_ret() so they can share a cache line.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/eadaf5530b46a7ae8b936522da45ae555d2b3393.1693889988.git.jpoimboe@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9d98aa088386aee3db1b7b60b800c0fde0654a4a upstream.
Adjust the IP passed to `emit_patch` so it calculates the correct offset
for the CALL instruction if `x86_call_depth_emit_accounting` emits code.
Otherwise we will skip some instructions and most likely crash.
Fixes: b2e9dfe54be4 ("x86/bpf: Emit call depth accounting if required")
Link: https://lore.kernel.org/lkml/20230105214922.250473-1-joanbrugueram@gmail.com/
Co-developed-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Signed-off-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20240401185821.224068-2-ubizjak@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8cb4a9a82b21623dbb4b3051dd30d98356cf95bc upstream.
Add CPUID_LNX_5 to track cpufeatures' word 21, and add the appropriate
compile-time assert in KVM to prevent direct lookups on the features in
CPUID_LNX_5. KVM uses X86_FEATURE_* flags to manage guest CPUID, and so
must translate features that are scattered by Linux from the Linux-defined
bit to the hardware-defined bit, i.e. should never try to directly access
scattered features in guest CPUID.
Opportunistically add NR_CPUID_WORDS to enum cpuid_leafs, along with a
compile-time assert in KVM's CPUID infrastructure to ensure that future
additions update cpuid_leafs along with NCAPINTS.
No functional change intended.
Fixes: 7f274e609f3d ("x86/cpufeatures: Add new word for scattered features")
Cc: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 598c2fafc06fe5c56a1a415fb7b544b31453d637 ]
Currently, the LBR code assumes that LBR Freeze is supported on all processors
when X86_FEATURE_AMD_LBR_V2 is available i.e. CPUID leaf 0x80000022[EAX]
bit 1 is set. This is incorrect as the availability of the feature is
additionally dependent on CPUID leaf 0x80000022[EAX] bit 2 being set,
which may not be set for all Zen 4 processors.
Define a new feature bit for LBR and PMC freeze and set the freeze enable bit
(FLBRI) in DebugCtl (MSR 0x1d9) conditionally.
It should still be possible to use LBR without freeze for profile-guided
optimization of user programs by using an user-only branch filter during
profiling. When the user-only filter is enabled, branches are no longer
recorded after the transition to CPL 0 upon PMI arrival. When branch
entries are read in the PMI handler, the branch stack does not change.
E.g.
$ perf record -j any,u -e ex_ret_brn_tkn ./workload
Since the feature bit is visible under flags in /proc/cpuinfo, it can be
used to determine the feasibility of use-cases which require LBR Freeze
to be supported by the hardware such as profile-guided optimization of
kernels.
Fixes: ca5b7c0d9621 ("perf/x86/amd/lbr: Add LbrExtV2 branch record support")
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/69a453c97cfd11c6f2584b19f937fe6df741510f.1711091584.git.sandipan.das@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7f274e609f3d5f45c22b1dd59053f6764458b492 ]
Add a new word for scattered features because all free bits among the
existing Linux-defined auxiliary flags have been exhausted.
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/8380d2a0da469a1f0ad75b8954a79fb689599ff6.1711091584.git.sandipan.das@amd.com
Stable-dep-of: 598c2fafc06f ("perf/x86/amd/lbr: Use freeze based on availability")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c7b2edd8377be983442c1344cb940cd2ac21b601 ]
AMD processors based on Zen 2 and later microarchitectures do not
support PMCx087 (instruction pipe stalls) which is used as the backing
event for "stalled-cycles-frontend" and "stalled-cycles-backend".
Use PMCx0A9 (cycles where micro-op queue is empty) instead to count
frontend stalls and remove the entry for backend stalls since there
is no direct replacement.
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Fixes: 3fe3331bb285 ("perf/x86/amd: Add event map for AMD Family 17h")
Link: https://lore.kernel.org/r/03d7fc8fa2a28f9be732116009025bdec1b3ec97.1711352180.git.sandipan.das@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 232afb557835d6f6859c73bf610bad308c96b131 ]
Add a synthetic feature flag specifically for first generation Zen
machines. There's need to have a generic flag for all Zen generations so
make X86_FEATURE_ZEN be that flag.
Fixes: 30fa92832f40 ("x86/CPU/AMD: Add ZenX generations flags")
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/dc3835e3-0731-4230-bbb9-336bbe3d042b@amd.com
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 54c33e23f75d5c9925495231c57d3319336722ef ]
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: http://lore.kernel.org/r/20231120104152.13740-10-bp@alien8.de
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit bfff3c6692ce64fa9d86eb829d18229c307a0855 ]
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: http://lore.kernel.org/r/20231120104152.13740-9-bp@alien8.de
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f69759be251dce722942594fbc62e53a40822a82 ]
Prefix it properly so that it is clear which generation it is dealing
with.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: http://lore.kernel.org/r/20231120104152.13740-8-bp@alien8.de
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0da91912fc150d6d321b15e648bead202ced1a27 ]
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: http://lore.kernel.org/r/20231120104152.13740-5-bp@alien8.de
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a7c32a1ae9ee43abfe884f5af376877c4301d166 ]
Call it on the affected CPU generations.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: http://lore.kernel.org/r/20231120104152.13740-3-bp@alien8.de
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 30fa92832f405d5ac9f263e99f62445fa3084008 ]
Add X86_FEATURE flags for each Zen generation. They should be used from
now on instead of checking f/m/s.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/r/20231120104152.13740-2-bp@alien8.de
Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c567f2948f57bdc03ed03403ae0234085f376b7d ]
This reverts commit d794734c9bbfe22f86686dc2909c25f5ffe1a572.
While the original change tries to fix a bug, it also unintentionally broke
existing systems, see the regressions reported at:
https://lore.kernel.org/all/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@pavinjoseph.com/
Since d794734c9bbf was also marked for -stable, let's back it out before
causing more damage.
Note that due to another upstream change the revert was not 100% automatic:
0a845e0f6348 mm/treewide: replace pud_large() with pud_leaf()
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Russ Anderson <rja@hpe.com>
Cc: Steve Wahl <steve.wahl@hpe.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@pavinjoseph.com/
Fixes: d794734c9bbf ("x86/mm/ident_map: Use gbpages only where full GB page should be mapped.")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0a845e0f6348ccfa2dcc8c450ffd1c9ffe8c4add ]
pud_large() is always defined as pud_leaf(). Merge their usages. Chose
pud_leaf() because pud_leaf() is a global API, while pud_large() is not.
Link: https://lkml.kernel.org/r/20240305043750.93762-9-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: c567f2948f57 ("Revert "x86/mm/ident_map: Use gbpages only where full GB page should be mapped."")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 0f4a1e80989aca185d955fcd791d7750082044a2 upstream.
SEV-SNP requires encrypted memory to be validated before access.
Because the ROM memory range is not part of the e820 table, it is not
pre-validated by the BIOS. Therefore, if a SEV-SNP guest kernel wishes
to access this range, the guest must first validate the range.
The current SEV-SNP code does indeed scan the ROM range during early
boot and thus attempts to validate the ROM range in probe_roms().
However, this behavior is neither sufficient nor necessary for the
following reasons:
* With regards to sufficiency, if EFI_CONFIG_TABLES are not enabled and
CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK is set, the kernel will
attempt to access the memory at SMBIOS_ENTRY_POINT_SCAN_START (which
falls in the ROM range) prior to validation.
For example, Project Oak Stage 0 provides a minimal guest firmware
that currently meets these configuration conditions, meaning guests
booting atop Oak Stage 0 firmware encounter a problematic call chain
during dmi_setup() -> dmi_scan_machine() that results in a crash
during boot if SEV-SNP is enabled.
* With regards to necessity, SEV-SNP guests generally read garbage
(which changes across boots) from the ROM range, meaning these scans
are unnecessary. The guest reads garbage because the legacy ROM range
is unencrypted data but is accessed via an encrypted PMD during early
boot (where the PMD is marked as encrypted due to potentially mapping
actually-encrypted data in other PMD-contained ranges).
In one exceptional case, EISA probing treats the ROM range as
unencrypted data, which is inconsistent with other probing.
Continuing to allow SEV-SNP guests to use garbage and to inconsistently
classify ROM range encryption status can trigger undesirable behavior.
For instance, if garbage bytes appear to be a valid signature, memory
may be unnecessarily reserved for the ROM range. Future code or other
use cases may result in more problematic (arbitrary) behavior that
should be avoided.
While one solution would be to overhaul the early PMD mapping to always
treat the ROM region of the PMD as unencrypted, SEV-SNP guests do not
currently rely on data from the ROM region during early boot (and even
if they did, they would be mostly relying on garbage data anyways).
As a simpler solution, skip the ROM range scans (and the otherwise-
necessary range validation) during SEV-SNP guest early boot. The
potential SEV-SNP guest crash due to lack of ROM range validation is
thus avoided by simply not accessing the ROM range.
In most cases, skip the scans by overriding problematic x86_init
functions during sme_early_init() to SNP-safe variants, which can be
likened to x86_init overrides done for other platforms (ex: Xen); such
overrides also avoid the spread of cc_platform_has() checks throughout
the tree.
In the exceptional EISA case, still use cc_platform_has() for the
simplest change, given (1) checks for guest type (ex: Xen domain status)
are already performed here, and (2) these checks occur in a subsys
initcall instead of an x86_init function.
[ bp: Massage commit message, remove "we"s. ]
Fixes: 9704c07bf9f7 ("x86/kernel: Validate ROM memory before accessing when SEV-SNP is active")
Signed-off-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20240313121546.2964854-1-kevinloughlin@google.com
Signed-off-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 532a0c57d7ff75e8f07d4e25cba4184989e2a241 upstream.
This was reverts commit 8009479ee919b9a91674f48050ccbff64eafedaa.
It was originally in x86/urgent, but was deemed wrong so got zapped.
But in the meantime, x86/urgent had been merged into x86/apic to
resolve a conflict. I didn't notice the merge so didn't zap it
from x86/apic and it managed to make it up with the x86/apic
material.
The reverted commit is known to cause some KASAN problems.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8009479ee919b9a91674f48050ccbff64eafedaa upstream.
The macro used for MDS mitigation executes VERW with relative
addressing for the operand. This was necessary in earlier versions of
the series. Now it is unnecessary and creates a problem for backports
on older kernels that don't support relocations in alternatives.
Relocation support was added by commit 270a69c4485d ("x86/alternative:
Support relocations in alternatives"). Also asm for fixed addressing
is much cleaner than relative RIP addressing.
Simplify the asm by using fixed addressing for VERW operand.
[ dhansen: tweak changelog ]
Closes: https://lore.kernel.org/lkml/20558f89-299b-472e-9a96-171403a83bd6@suse.com/
Fixes: baf8361e5455 ("x86/bugs: Add asm helpers for executing VERW")
Reported-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240226-verw-arg-fix-v1-1-7b37ee6fd57d%40linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d21f5a59ea773826cc489acb287811d690b703cc upstream.
The pure EFI stub entry point does not take a struct boot_params from
the boot loader, but creates it from scratch, and populates only the
fields that still have meaning in this context (command line, initrd
base and size, etc)
The original mixed mode implementation used the EFI handover protocol
instead, where the boot loader (i.e., GRUB) populates a boot_params
struct and passes it to a special Linux specific EFI entry point that
takes the boot_params pointer as its third argument.
When the new mixed mode implementation was introduced, using a special
32-bit PE entrypoint in the 64-bit kernel, it adopted the pure approach,
and relied on the EFI stub to create the struct boot_params. This is
preferred because it makes the bootloader side much easier to implement,
as it does not need any x86-specific knowledge on how struct boot_params
and struct setup_header are put together. This mixed mode implementation
was adopted by systemd-boot version 252 and later.
When commit
e2ab9eab324c ("x86/boot/compressed: Move 32-bit entrypoint code into .text section")
refactored this code and moved it out of head_64.S, the fact that ESI
was populated with the address of the base of the image was overlooked,
and to simplify the code flow, ESI is now zeroed and stored to memory
unconditionally in shared code, so that the NULL-ness of that variable
can still be used later to determine which mixed mode boot protocol is
in use.
With ESI pointing to the base of the image, it can serve as a struct
boot_params pointer for startup_32(), which only accesses the init_data
and kernel_alignment fields (and the scratch field as a temporary
stack). Zeroing ESI means that those accesses produce garbage now, even
though things appear to work if the first page of memory happens to be
zeroed, and the region right before LOAD_PHYSICAL_ADDR (== 16 MiB)
happens to be free.
The solution is to pass a special, temporary struct boot_params to
startup_32() via ESI, one that is sufficient for getting it to create
the page tables correctly and is discarded right after. This involves
setting a minimal alignment of 4k, only to get the statically allocated
page tables line up correctly, and setting init_size to the executable
image size (_end - startup_32). This ensures that the page tables are
covered by the static footprint of the PE image.
Given that EFI boot no longer calls the decompressor and no longer pads
the image to permit the decompressor to execute in place, the same
temporary struct boot_params should be used in the EFI handover protocol
based mixed mode implementation as well, to prevent the page tables from
being placed outside of allocated memory.
Fixes: e2ab9eab324c ("x86/boot/compressed: Move 32-bit entrypoint code into .text section")
Cc: <stable@kernel.org> # v6.1+
Closes: https://lore.kernel.org/all/20240321150510.GI8211@craftyguy.net/
Reported-by: Clayton Craft <clayton@craftyguy.net>
Tested-by: Clayton Craft <clayton@craftyguy.net>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 10e4b5166df9ff7a2d5316138ca668b42d004422 ]
Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and
commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a
per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in
order to avoid unnecessary writes to the MSR.
On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which
wipes out any stale state. But the per CPU cached xfd value is not
reset, which brings them out of sync.
As a consequence a subsequent xfd_update_state() might fail to update
the MSR which in turn can result in XRSTOR raising a #NM in kernel
space, which crashes the kernel.
To fix this, introduce xfd_set_state() to write xfd_state together
with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.
Fixes: 672365477ae8 ("x86/fpu: Update XFD state where required")
Signed-off-by: Adamos Ttofari <attofari@amazon.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240322230439.456571-1-chang.seok.bae@intel.com
Closes: https://lore.kernel.org/lkml/20230511152818.13839-1-attofari@amazon.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f2208aa12c27bfada3c15c550c03ca81d42dcac2 ]
The APIC address is registered twice. First during the early detection and
afterwards when actually scanning the table for APIC IDs. The APIC and
topology core warn about the second attempt.
Restrict it to the early detection call.
Fixes: 81287ad65da5 ("x86/apic: Sanitize APIC address setup")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240322185305.297774848@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 4e51653d5d871f40f1bd5cf95cc7f2d8b33d063b ]
Read from an unsafe address with copy_from_kernel_nofault() in
arch_adjust_kprobe_addr() because this function is used before checking
the address is in text or not. Syzcaller bot found a bug and reported
the case if user specifies inaccessible data area,
arch_adjust_kprobe_addr() will cause a kernel panic.
[ mingo: Clarified the comment. ]
Fixes: cc66bb914578 ("x86/ibt,kprobes: Cure sym+0 equals fentry woes")
Reported-by: Qiang Zhang <zzqq0103.hey@gmail.com>
Tested-by: Jinghao Jia <jinghao7@illinois.edu>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/171042945004.154897.2221804961882915806.stgit@devnote2
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 1c811d403afd73f04bde82b83b24c754011bd0e8 upstream.
The early startup code executes from a 1:1 mapping of memory, which
differs from the mapping that the code was linked and/or relocated to
run at. The latter mapping is not active yet at this point, and so
symbol references that rely on it will fault.
Given that the core kernel is built without -fPIC, symbol references are
typically emitted as absolute, and so any such references occuring in
the early startup code will therefore crash the kernel.
While an attempt was made to work around this for the early SEV/SME
startup code, by forcing RIP-relative addressing for certain global
SEV/SME variables via inline assembly (see snp_cpuid_get_table() for
example), RIP-relative addressing must be pervasively enforced for
SEV/SME global variables when accessed prior to page table fixups.
__startup_64() already handles this issue for select non-SEV/SME global
variables using fixup_pointer(), which adjusts the pointer relative to a
`physaddr` argument. To avoid having to pass around this `physaddr`
argument across all functions needing to apply pointer fixups, introduce
a macro RIP_RELATIVE_REF() which generates a RIP-relative reference to
a given global variable. It is used where necessary to force
RIP-relative accesses to global variables.
For backporting purposes, this patch makes no attempt at cleaning up
other occurrences of this pattern, involving either inline asm or
fixup_pointer(). Those will be addressed later.
[ bp: Call it "rip_rel_ref" everywhere like other code shortens
"rIP-relative reference" and make the asm wrapper __always_inline. ]
Co-developed-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/all/20240130220845.1978329-1-kevinloughlin@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 29956748339aa8757a7e2f927a8679dd08f24bb6 upstream.
It was meant well at the time but nothing's using it so get rid of it.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240202163510.GDZb0Zvj8qOndvFOiZ@fat_crate.local
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cefcd4fe2e3aaf792c14c9e56dab89e3d7a65d02 upstream.
Normally, the EFI stub calls into the EFI boot services using the stack
that was live when the stub was entered. According to the UEFI spec,
this stack needs to be at least 128k in size - this might seem large but
all asynchronous processing and event handling in EFI runs from the same
stack and so quite a lot of space may be used in practice.
In mixed mode, the situation is a bit different: the bootloader calls
the 32-bit EFI stub entry point, which calls the decompressor's 32-bit
entry point, where the boot stack is set up, using a fixed allocation
of 16k. This stack is still in use when the EFI stub is started in
64-bit mode, and so all calls back into the EFI firmware will be using
the decompressor's limited boot stack.
Due to the placement of the boot stack right after the boot heap, any
stack overruns have gone unnoticed. However, commit
5c4feadb0011983b ("x86/decompressor: Move global symbol references to C code")
moved the definition of the boot heap into C code, and now the boot
stack is placed right at the base of BSS, where any overruns will
corrupt the end of the .data section.
While it would be possible to work around this by increasing the size of
the boot stack, doing so would affect all x86 systems, and mixed mode
systems are a tiny (and shrinking) fraction of the x86 installed base.
So instead, record the firmware stack pointer value when entering from
the 32-bit firmware, and switch to this stack every time a EFI boot
service call is made.
Cc: <stable@kernel.org> # v6.1+
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5abf6dceb066f2b02b225fd561440c98a8062681 upstream.
The DebugSwap feature of SEV-ES provides a way for confidential guests to use
data breakpoints. However, because the status of the DebugSwap feature is
recorded in the VMSA, enabling it by default invalidates the attestation
signatures. In 6.10 we will introduce a new API to create SEV VMs that
will allow enabling DebugSwap based on what the user tells KVM to do.
Contextually, we will change the legacy KVM_SEV_ES_INIT API to never
enable DebugSwap.
For compatibility with kernels that pre-date the introduction of DebugSwap,
as well as with those where KVM_SEV_ES_INIT will never enable it, do not enable
the feature by default. If anybody wants to use it, for now they can enable
the sev_es_debug_swap_enabled module parameter, but this will result in a
warning.
Fixes: d1f85fbe836e ("KVM: SEV: Enable data breakpoints in SEV-ES")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807 upstream.
Do the cache flush of converted pages in svm_register_enc_region() before
dropping kvm->lock to fix use-after-free issues where region and/or its
array of pages could be freed by a different task, e.g. if userspace has
__unregister_enc_region_locked() already queued up for the region.
Note, the "obvious" alternative of using local variables doesn't fully
resolve the bug, as region->pages is also dynamically allocated. I.e. the
region structure itself would be fine, but region->pages could be freed.
Flushing multiple pages under kvm->lock is unfortunate, but the entire
flow is a rare slow path, and the manual flush is only needed on CPUs that
lack coherency for encrypted memory.
Fixes: 19a23da53932 ("Fix unsynchronized access to sev members through svm_register_enc_region")
Reported-by: Gabe Kirkpatrick <gkirkpatrick@google.com>
Cc: Josh Eads <josheads@google.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20240217013430.2079561-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 910c57dfa4d113aae6571c2a8b9ae8c430975902 upstream.
When emulating an atomic access on behalf of the guest, mark the target
gfn dirty if the CMPXCHG by KVM is attempted and doesn't fault. This
fixes a bug where KVM effectively corrupts guest memory during live
migration by writing to guest memory without informing userspace that the
page is dirty.
Marking the page dirty got unintentionally dropped when KVM's emulated
CMPXCHG was converted to do a user access. Before that, KVM explicitly
mapped the guest page into kernel memory, and marked the page dirty during
the unmap phase.
Mark the page dirty even if the CMPXCHG fails, as the old data is written
back on failure, i.e. the page is still written. The value written is
guaranteed to be the same because the operation is atomic, but KVM's ABI
is that all writes are dirty logged regardless of the value written. And
more importantly, that's what KVM did before the buggy commit.
Huge kudos to the folks on the Cc list (and many others), who did all the
actual work of triaging and debugging.
Fixes: 1c2361f667f3 ("KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses")
Cc: stable@vger.kernel.org
Cc: David Matlack <dmatlack@google.com>
Cc: Pasha Tatashin <tatashin@google.com>
Cc: Michael Krebs <mkrebs@google.com>
base-commit: 6769ea8da8a93ed4630f1ce64df6aafcaabfce64
Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20240215010004.1456078-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit e3f269ed0accbb22aa8f25d2daffa23c3fccd407 ]
Since:
7ee18d677989 ("x86/power: Make restore_processor_context() sane")
kmemleak reports this issue:
unreferenced object 0xf68241e0 (size 32):
comm "swapper/0", pid 1, jiffies 4294668610 (age 68.432s)
hex dump (first 32 bytes):
00 cc cc cc 29 10 01 c0 00 00 00 00 00 00 00 00 ....)...........
00 42 82 f6 cc cc cc cc cc cc cc cc cc cc cc cc .B..............
backtrace:
[<461c1d50>] __kmem_cache_alloc_node+0x106/0x260
[<ea65e13b>] __kmalloc+0x54/0x160
[<c3858cd2>] msr_build_context.constprop.0+0x35/0x100
[<46635aff>] pm_check_save_msr+0x63/0x80
[<6b6bb938>] do_one_initcall+0x41/0x1f0
[<3f3add60>] kernel_init_freeable+0x199/0x1e8
[<3b538fde>] kernel_init+0x1a/0x110
[<938ae2b2>] ret_from_fork+0x1c/0x28
Which is a false positive.
Reproducer:
- Run rsync of whole kernel tree (multiple times if needed).
- start a kmemleak scan
- Note this is just an example: a lot of our internal tests hit these.
The root cause is similar to the fix in:
b0b592cf0836 x86/pm: Fix false positive kmemleak report in msr_build_context()
ie. the alignment within the packed struct saved_context
which has everything unaligned as there is only "u16 gs;" at start of
struct where in the past there were four u16 there thus aligning
everything afterwards. The issue is with the fact that Kmemleak only
searches for pointers that are aligned (see how pointers are scanned in
kmemleak.c) so when the struct members are not aligned it doesn't see
them.
Testing:
We run a lot of tests with our CI, and after applying this fix we do not
see any kmemleak issues any more whilst without it we see hundreds of
the above report. From a single, simple test run consisting of 416 individual test
cases on kernel 5.10 x86 with kmemleak enabled we got 20 failures due to this,
which is quite a lot. With this fix applied we get zero kmemleak related failures.
Fixes: 7ee18d677989 ("x86/power: Make restore_processor_context() sane")
Signed-off-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240314142656.17699-1-anton@tuxera.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 5c84b051bd4e777cf37aaff983277e58c99618d5 ]
Update them to the correct revision numbers.
Fixes: 522b1d69219d ("x86/cpu/amd: Add a Zenbleed fix")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 8e62bf2bfa46367e14d0ffdcde5aada08759497c ]
Linux guests since commit b1c3497e604d ("x86/xen: Add support for
HVMOP_set_evtchn_upcall_vector") in v6.0 onwards will use the per-vCPU
upcall vector when it's advertised in the Xen CPUID leaves.
This upcall is injected through the guest's local APIC as an MSI, unlike
the older system vector which was merely injected by the hypervisor any
time the CPU was able to receive an interrupt and the upcall_pending
flags is set in its vcpu_info.
Effectively, that makes the per-CPU upcall edge triggered instead of
level triggered, which results in the upcall being lost if the MSI is
delivered when the local APIC is *disabled*.
Xen checks the vcpu_info->evtchn_upcall_pending flag when the local APIC
for a vCPU is software enabled (in fact, on any write to the SPIV
register which doesn't disable the APIC). Do the same in KVM since KVM
doesn't provide a way for userspace to intervene and trap accesses to
the SPIV register of a local APIC emulated by KVM.
Fixes: fde0451be8fb3 ("KVM: x86/xen: Support per-vCPU event channel upcall via local APIC")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240227115648.3104-3-dwmw2@infradead.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d54e56f31a34fa38fcb5e91df609f9633419a79a ]
Commit 344da544f177 ("x86/nmi: Print reasons why backtrace NMIs are
ignored") creates a super nice framework to diagnose NMIs.
Every time nmi_exc() is called, it increments a per_cpu counter
(nsp->idt_nmi_seq). At its exit, it also increments the same counter. By
reading this counter it can be seen how many times that function was called
(dividing by 2), and, if the function is still being executed, by checking
the idt_nmi_seq's least significant bit.
On the check side (nmi_backtrace_stall_check()), that variable is queried
to check if the NMI is still being executed, but, there is a mistake in the
bitwise operation. That code wants to check if the least significant bit of
the idt_nmi_seq is set or not, but does the opposite, and checks for all
the other bits, which will always be true after the first exc_nmi()
executed successfully.
This appends the misleading string to the dump "(CPU currently in NMI
handler function)"
Fix it by checking the least significant bit, and if it is set, append the
string.
Fixes: 344da544f177 ("x86/nmi: Print reasons why backtrace NMIs are ignored")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240207165237.1048837-1-leitao@debian.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 80c883db87d9ffe2d685e91ba07a087b1c246c78 upstream.
Use a switch statement with macro-generated case statements to handle
translating feature flags in order to reduce the probability of runtime
errors due to copy+paste goofs, to make compile-time errors easier to
debug, and to make the code more readable.
E.g. the compiler won't directly generate an error for duplicate if
statements
if (x86_feature == X86_FEATURE_SGX1)
return KVM_X86_FEATURE_SGX1;
else if (x86_feature == X86_FEATURE_SGX2)
return KVM_X86_FEATURE_SGX1;
and so instead reverse_cpuid_check() will fail due to the untranslated
entry pointing at a Linux-defined leaf, which provides practically no
hint as to what is broken
arch/x86/kvm/reverse_cpuid.h:108:2: error: call to __compiletime_assert_450 declared with 'error' attribute:
BUILD_BUG_ON failed: x86_leaf == CPUID_LNX_4
BUILD_BUG_ON(x86_leaf == CPUID_LNX_4);
^
whereas duplicate case statements very explicitly point at the offending
code:
arch/x86/kvm/reverse_cpuid.h:125:2: error: duplicate case value '361'
KVM_X86_TRANSLATE_FEATURE(SGX2);
^
arch/x86/kvm/reverse_cpuid.h:124:2: error: duplicate case value '360'
KVM_X86_TRANSLATE_FEATURE(SGX1);
^
And without macros, the opposite type of copy+paste goof doesn't generate
any error at compile-time, e.g. this yields no complaints:
case X86_FEATURE_SGX1:
return KVM_X86_FEATURE_SGX1;
case X86_FEATURE_SGX2:
return KVM_X86_FEATURE_SGX1;
Note, __feature_translate() is forcibly inlined and the feature is known
at compile-time, so the code generation between an if-elif sequence and a
switch statement should be identical.
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20231024001636.890236-2-jmattson@google.com
[sean: use a macro, rewrite changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit eefe5e6682099445f77f2d97d4c525f9ac9d9b07 upstream.
The low five bits {INTEL_PSFD, IPRED_CTRL, RRSBA_CTRL, DDPD_U, BHI_CTRL}
advertise the availability of specific bits in IA32_SPEC_CTRL. Since KVM
dynamically determines the legal IA32_SPEC_CTRL bits for the underlying
hardware, the hard work has already been done. Just let userspace know
that a guest can use these IA32_SPEC_CTRL bits.
The sixth bit (MCDT_NO) states that the processor does not exhibit MXCSR
Configuration Dependent Timing (MCDT) behavior. This is an inherent
property of the physical processor that is inherited by the virtual
CPU. Pass that information on to userspace.
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20231024001636.890236-1-jmattson@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 2b4b90e053a29057fb05ba81acce26bddce8d404 ]
Currently, the secondary CPUs in Hyper-V VTL context lack support for
parallel startup. Therefore, relying on the single initial_stack fetched
from the current task structure suffices for all vCPUs.
However, common initial_stack risks stack corruption when parallel startup
is enabled. In order to facilitate parallel startup, use the initial_stack
from the per CPU idle thread instead of the current task.
Fixes: 3be1bc2fe9d2 ("x86/hyperv: VTL support for Hyper-V")
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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