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The check for early_is_amd_nb() is only useful for systems with GART or
the NB_CFG register.
Zen-based systems (both AMD and Hygon) have neither, so return early for
them.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241206161210.163701-4-yazen.ghannam@amd.com
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The code implicitly operates on AMD-based systems by matching on PCI
IDs. However, the use of these IDs is going away.
Add an explicit CPU vendor check instead of relying on PCI IDs.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241206161210.163701-3-yazen.ghannam@amd.com
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Remove includes of linux/hyperv.h, mshyperv.h, and hyperv-tlfs.h where
they are not used.
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Link: https://lore.kernel.org/r/1732577084-2122-3-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1732577084-2122-3-git-send-email-nunodasneves@linux.microsoft.com>
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The x86 shadow stack support has its own set of registers. Those registers
are XSAVE-managed, but they are "supervisor state components" which means
that userspace can not touch them with XSAVE/XRSTOR. It also means that
they are not accessible from the existing ptrace ABI for XSAVE state.
Thus, there is a new ptrace get/set interface for it.
The regset code that ptrace uses provides an ->active() handler in
addition to the get/set ones. For shadow stack this ->active() handler
verifies that shadow stack is enabled via the ARCH_SHSTK_SHSTK bit in the
thread struct. The ->active() handler is checked from some call sites of
the regset get/set handlers, but not the ptrace ones. This was not
understood when shadow stack support was put in place.
As a result, both the set/get handlers can be called with
XFEATURE_CET_USER in its init state, which would cause get_xsave_addr() to
return NULL and trigger a WARN_ON(). The ssp_set() handler luckily has an
ssp_active() check to avoid surprising the kernel with shadow stack
behavior when the kernel is not ready for it (ARCH_SHSTK_SHSTK==0). That
check just happened to avoid the warning.
But the ->get() side wasn't so lucky. It can be called with shadow stacks
disabled, triggering the warning in practice, as reported by Christina
Schimpe:
WARNING: CPU: 5 PID: 1773 at arch/x86/kernel/fpu/regset.c:198 ssp_get+0x89/0xa0
[...]
Call Trace:
<TASK>
? show_regs+0x6e/0x80
? ssp_get+0x89/0xa0
? __warn+0x91/0x150
? ssp_get+0x89/0xa0
? report_bug+0x19d/0x1b0
? handle_bug+0x46/0x80
? exc_invalid_op+0x1d/0x80
? asm_exc_invalid_op+0x1f/0x30
? __pfx_ssp_get+0x10/0x10
? ssp_get+0x89/0xa0
? ssp_get+0x52/0xa0
__regset_get+0xad/0xf0
copy_regset_to_user+0x52/0xc0
ptrace_regset+0x119/0x140
ptrace_request+0x13c/0x850
? wait_task_inactive+0x142/0x1d0
? do_syscall_64+0x6d/0x90
arch_ptrace+0x102/0x300
[...]
Ensure that shadow stacks are active in a thread before looking them up
in the XSAVE buffer. Since ARCH_SHSTK_SHSTK and user_ssp[SHSTK_EN] are
set at the same time, the active check ensures that there will be
something to find in the XSAVE buffer.
[ dhansen: changelog/subject tweaks ]
Fixes: 2fab02b25ae7 ("x86: Add PTRACE interface for shadow stack")
Reported-by: Christina Schimpe <christina.schimpe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Christina Schimpe <christina.schimpe@intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250107233056.235536-1-rick.p.edgecombe%40intel.com
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In SNP guest environment with Secure TSC enabled, unlike other clock sources
(such as HPET, ACPI timer, APIC, etc), the RDTSC instruction is handled
without causing a VM exit, resulting in minimal overhead and jitters. Even
when the host CPU's TSC is tampered with, the Secure TSC enabled guest keeps
on ticking forward. Hence, mark Secure TSC as the only reliable clock source,
bypassing unstable calibration.
[ bp: Massage. ]
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Peter Gonda <pgonda@google.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-10-nikunj@amd.com
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The hypervisor should not be intercepting RDTSC/RDTSCP when Secure TSC is
enabled. A #VC exception will be generated if the RDTSC/RDTSCP instructions
are being intercepted. If this should occur and Secure TSC is enabled,
guest execution should be terminated as the guest cannot rely on the TSC
value provided by the hypervisor.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Peter Gonda <pgonda@google.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-9-nikunj@amd.com
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The hypervisor should not be intercepting GUEST_TSC_FREQ MSR(0xcOO10134)
when Secure TSC is enabled. A #VC exception will be generated otherwise. If
this should occur and Secure TSC is enabled, terminate guest execution.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-8-nikunj@amd.com
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Secure TSC enabled guests should not write to the MSR_IA32_TSC (0x10) register
as the subsequent TSC value reads are undefined. On AMD, MSR_IA32_TSC is
intercepted by the hypervisor by default. MSR_IA32_TSC read/write accesses
should not exit to the hypervisor for such guests.
Accesses to MSR_IA32_TSC need special handling in the #VC handler for the
guests with Secure TSC enabled. Writes to MSR_IA32_TSC should be ignored and
flagged once with a warning, and reads of MSR_IA32_TSC should return the
result of the RDTSC instruction.
[ bp: Massage commit message. ]
Suggested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-7-nikunj@amd.com
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Add support for Secure TSC in SNP-enabled guests. Secure TSC allows guests
to securely use RDTSC/RDTSCP instructions, ensuring that the parameters used
cannot be altered by the hypervisor once the guest is launched.
Secure TSC-enabled guests need to query TSC information from the AMD Security
Processor. This communication channel is encrypted between the AMD Security
Processor and the guest, with the hypervisor acting merely as a conduit to
deliver the guest messages to the AMD Security Processor. Each message is
protected with AEAD (AES-256 GCM).
[ bp: Zap a stray newline over amd_cc_platform_has() while at it,
simplify CC_ATTR_GUEST_SNP_SECURE_TSC check ]
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250106124633.1418972-6-nikunj@amd.com
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Commit
09d35045cd0f ("x86/sev: Avoid WARN()s and panic()s in early boot code")
replaced a panic() that could potentially hit before the kernel is even
mapped with a deadloop, to ensure that execution does not proceed when the
condition in question hits.
As Tom suggests, it is better to terminate and return to the hypervisor
in this case, using a newly invented failure code to describe the
failure condition.
Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/all/9ce88603-20ca-e644-2d8a-aeeaf79cde69@amd.com
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At present, the SEV guest driver exclusively handles SNP guest messaging. All
routines for sending guest messages are embedded within it.
To support Secure TSC, SEV-SNP guests must communicate with the AMD Security
Processor during early boot. However, these guest messaging functions are not
accessible during early boot since they are currently part of the guest
driver.
Hence, relocate the core SNP guest messaging functions to SEV common code and
provide an API for sending SNP guest messages.
No functional change, but just an export symbol added for
snp_send_guest_request() and dropped the export symbol on
snp_issue_guest_request() and made it static.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-5-nikunj@amd.com
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Currently, the sev-guest driver is the only user of SNP guest messaging. All
routines for initializing SNP guest messaging are implemented within the
sev-guest driver and are not available during early boot.
In preparation for adding Secure TSC guest support, carve out APIs to allocate
and initialize the guest messaging descriptor context and make it part of
coco/sev/core.c. As there is no user of sev_guest_platform_data anymore,
remove the structure.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-4-nikunj@amd.com
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Legacy AMD systems include an integrated Northbridge that is represented
by MCA bank 4. This is the only non-core MCA bank in legacy systems. The
Northbridge is physically shared by all the CPUs within an AMD "Node".
However, in practice the "shared" MCA bank can only by managed by a
single CPU within that AMD Node. This is known as the "Node Base Core"
(NBC). For example, only the NBC will be able to read the MCA bank 4
registers; they will be Read-as-Zero for other CPUs. Also, the MCA
Thresholding interrupt will only signal the NBC; the other CPUs will not
receive it. This is enforced by hardware, and it should not be managed by
software.
The current AMD Thresholding code attempts to deal with the "shared" MCA
bank by micromanaging the bank's sysfs kobjects. However, this does not
follow the intended kobject use cases. It is also fragile, and it has
caused bugs in the past.
Modern AMD systems do not need this shared MCA bank support, and it
should not be needed on legacy systems either.
Remove the shared threshold bank code. Also, move the threshold struct
definitions to mce/amd.c, since they are no longer needed in amd_nb.c.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241206161210.163701-2-yazen.ghannam@amd.com
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The type "physic al" should be "physical".
[ bp: Massage commit message. ]
Fixes: 54cd3795b471 ("x86/ioapic: Cleanup guarded debug printk()s")
Signed-off-by: Alan Song <syfmark114@163.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241230065706.16789-1-syfmark114@163.com
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__static_call_update_early() has a check for early_boot_irqs_disabled, but
is used before early_boot_irqs_disabled is set up in start_kernel().
Xen PV has always special cased early_boot_irqs_disabled, but Xen PVH does
not and falls over the BUG when booting as dom0.
It is very suspect that early_boot_irqs_disabled starts as 0, becomes 1 for
a time, then becomes 0 again, but as this needs backporting to fix a
breakage in a security fix, dropping the BUG_ON() is the far safer option.
Fixes: 0ef8047b737d ("x86/static-call: provide a way to do very early static-call updates")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219620
Reported-by: Alex Zenla <alex@edera.dev>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alex Zenla <alex@edera.dev>
Link: https://lore.kernel.org/r/20241221211046.6475-1-andrew.cooper3@citrix.com
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Clang 14 and older may emit UBSAN instrumentation into code that is
inlined into functions marked with __no_sanitize_undefined¹. This may
result in faults when the code is executed very early, which may be the
case for functions annotated as __head. Now that this requirement is
strictly enforced, the build will fail in this case with the following
message
Absolute reference to symbol '.data' not permitted in .head.text
Work around this by disabling UBSAN instrumentation on all SEV core
code.
¹ https://lore.kernel.org/r/20250101024348.GA1828419@ax162
[ bp: Add a footnote with Nathan's detailed explanation and a Fixes
tag ]
Fixes: 3b6f99a94b04 ("x86/boot: Disable UBSAN in early boot code")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250101115119.114584-2-ardb@kernel.org
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No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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This is the natural thing to do anyway.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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The result of that function is in essence boolean, so simplify to return the
result of the relevant expression. It also makes it follow the convention used
by __verify_patch_section().
No functional changes.
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241018155151.702350-3-nik.borisov@suse.com
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The function doesn't return an equivalence ID, remove the false comment.
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241018155151.702350-4-nik.borisov@suse.com
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Instead of open-coding the check for size/data move it inside the
function and make it return a boolean indicating whether data was found
or not.
No functional changes.
[ bp: Write @ret in find_blobs_in_containers() only on success. ]
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241018155151.702350-2-nik.borisov@suse.com
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Get HYGON to directly call mce_amd_feature_init() and remove the redundant
mce_hygon_feature_init().
Suggested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20241212140103.66964-7-qiuxu.zhuo@intel.com
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Convert family/model mixed checks to VFM-based checks to make the code
more compact. Simplify.
[ bp: Drop the "what" from the commit message - it should be visible from
the diff alone. ]
Suggested-by: Sohil Mehta <sohil.mehta@intel.com>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20241212140103.66964-6-qiuxu.zhuo@intel.com
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Split each vendor specific part into its own helper function.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Tested-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20241212140103.66964-5-qiuxu.zhuo@intel.com
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Make those functions whose callers only care about success or failure return
a boolean value for better readability. Also, update the call sites
accordingly as the polarities of all the return values have been flipped.
No functional changes.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20241212140103.66964-4-qiuxu.zhuo@intel.com
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The 'storm' variable points to this_cpu_ptr(&storm_desc). Access the
'stormy_bank_count' field through the 'storm' to avoid calling
this_cpu_*() on the same per-CPU variable twice.
This minor optimization reduces the text size by 16 bytes.
$ size threshold.o.*
text data bss dec hex filename
1395 1664 0 3059 bf3 threshold.o.old
1379 1664 0 3043 be3 threshold.o.new
No functional changes intended.
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20241212140103.66964-3-qiuxu.zhuo@intel.com
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Make several functions that return 0 or 1 return a boolean value for
better readability.
No functional changes are intended.
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20241212140103.66964-2-qiuxu.zhuo@intel.com
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0x8000001f.EAX is an AMD-specific leaf so there's no need to have "AMD"
in almost every feature's comment. Zap it and make the text more
readable this way.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241122210707.12742-1-bp@kernel.org
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SRSO_USER_KERNEL_NO denotes whether the CPU is affected by SRSO across
user/kernel boundaries. Advertise it to guest userspace.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/20241202120416.6054-3-bp@kernel.org
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If the machine has:
CPUID Fn8000_0021_EAX[30] (SRSO_USER_KERNEL_NO) -- If this bit is 1,
it indicates the CPU is not subject to the SRSO vulnerability across
user/kernel boundaries.
have it fall back to IBPB on VMEXIT only, in the case it is going to run
VMs:
Speculative Return Stack Overflow: Mitigation: IBPB on VMEXIT only
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/20241202120416.6054-2-bp@kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
- Fix a hang in the "kernel IBT no ENDBR" self-test that may trigger
on FRED systems, caused by incomplete FRED state cleanup in the
#CP fault handler
- Improve TDX (Coco VM) guest unrecoverable error handling to not
potentially leak decrypted memory
* tag 'x86-urgent-2024-12-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
virt: tdx-guest: Just leak decrypted memory on unrecoverable errors
x86/fred: Clear WFE in missing-ENDBRANCH #CPs
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf fixes from Ingo Molnar:
- Fix Intel Lunar Lake build-in event definitions
- Fall back to (compatible) legacy features on new Intel PEBS format v6
hardware
- Enable uncore support on Intel Clearwater Forest CPUs, which is the
same as the existing Sierra Forest uncore driver
* tag 'perf-urgent-2024-12-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Fix bitmask of OCR and FRONTEND events for LNC
perf/x86/intel/ds: Add PEBS format 6
perf/x86/intel/uncore: Add Clearwater Forest support
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An indirect branch instruction sets the CPU indirect branch tracker
(IBT) into WAIT_FOR_ENDBRANCH (WFE) state and WFE stays asserted
across the instruction boundary. When the decoder finds an
inappropriate instruction while WFE is set ENDBR, the CPU raises a #CP
fault.
For the "kernel IBT no ENDBR" selftest where #CPs are deliberately
triggered, the WFE state of the interrupted context needs to be
cleared to let execution continue. Otherwise when the CPU resumes
from the instruction that just caused the previous #CP, another
missing-ENDBRANCH #CP is raised and the CPU enters a dead loop.
This is not a problem with IDT because it doesn't preserve WFE and
IRET doesn't set WFE. But FRED provides space on the entry stack
(in an expanded CS area) to save and restore the WFE state, thus the
WFE state is no longer clobbered, so software must clear it.
Clear WFE to avoid dead looping in ibt_clear_fred_wfe() and the
!ibt_fatal code path when execution is allowed to continue.
Clobbering WFE in any other circumstance is a security-relevant bug.
[ dhansen: changelog rewording ]
Fixes: a5f6c2ace997 ("x86/shstk: Add user control-protection fault handler")
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20241113175934.3897541-1-xin%40zytor.com
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This introduces ftrace_get_symaddr() which tries to convert fentry_ip
passed by ftrace or fgraph callback to symaddr without calling
kallsyms API. It returns the symbol address or 0 if it fails to
convert it.
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/173519011487.391279.5450806886342723151.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202412061423.K79V55Hd-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202412061804.5VRzF14E-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Fprobe store its data structure address and size on the fgraph return stack
by __fprobe_header. But most 64bit architecture can combine those to
one unsigned long value because 4 MSB in the kernel address are the same.
With this encoding, fprobe can consume less space on ret_stack.
This introduces asm/fprobe.h to define arch dependent encode/decode
macros. Note that since fprobe depends on CONFIG_HAVE_FUNCTION_GRAPH_FREGS,
currently only arm64, loongarch, riscv, s390 and x86 are supported.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/173519005783.391279.5307910947400277525.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Rewrite fprobe implementation on function-graph tracer.
Major API changes are:
- 'nr_maxactive' field is deprecated.
- This depends on CONFIG_DYNAMIC_FTRACE_WITH_ARGS or
!CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS, and
CONFIG_HAVE_FUNCTION_GRAPH_FREGS. So currently works only
on x86_64.
- Currently the entry size is limited in 15 * sizeof(long).
- If there is too many fprobe exit handler set on the same
function, it will fail to probe.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/173519003970.391279.14406792285453830996.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Add CONFIG_HAVE_FTRACE_GRAPH_FUNC kconfig in addition to ftrace_graph_func
macro check. This is for the other feature (e.g. FPROBE) which requires to
access ftrace_regs from fgraph_ops::entryfunc() can avoid compiling if
the fgraph can not pass the valid ftrace_regs.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/173519001472.391279.1174901685282588467.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Add ftrace_fill_perf_regs() which should be compatible with the
perf_fetch_caller_regs(). In other words, the pt_regs returned from the
ftrace_fill_perf_regs() must satisfy 'user_mode(regs) == false' and can be
used for stack tracing.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/173518997908.391279.15910334347345106424.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Change the fprobe exit handler to use ftrace_regs structure instead of
pt_regs. This also introduce HAVE_FTRACE_REGS_HAVING_PT_REGS which
means the ftrace_regs is including the pt_regs so that ftrace_regs
can provide pt_regs without memory allocation.
Fprobe introduces a new dependency with that.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Song Liu <song@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Matt Bobrowski <mattbobrowski@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Hao Luo <haoluo@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/173518995092.391279.6765116450352977627.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Use ftrace_regs instead of fgraph_ret_regs for tracing return value
on function_graph tracer because of simplifying the callback interface.
The CONFIG_HAVE_FUNCTION_GRAPH_RETVAL is also replaced by
CONFIG_HAVE_FUNCTION_GRAPH_FREGS.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/173518991508.391279.16635322774382197642.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Pass ftrace_regs to the fgraph_ops::entryfunc(). If ftrace_regs is not
available, it passes a NULL instead. User callback function can access
some registers (including return address) via this ftrace_regs.
Note that the ftrace_regs can be NULL when the arch does NOT define:
HAVE_DYNAMIC_FTRACE_WITH_ARGS or HAVE_DYNAMIC_FTRACE_WITH_REGS.
More specifically, if HAVE_DYNAMIC_FTRACE_WITH_REGS is defined but
not the HAVE_DYNAMIC_FTRACE_WITH_ARGS, and the ftrace ops used to
register the function callback does not set FTRACE_OPS_FL_SAVE_REGS.
In this case, ftrace_regs can be NULL in user callback.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/173518990044.391279.17406984900626078579.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Get the ftrace recursion lock in the generic function_graph_enter()
instead of each architecture code.
This changes all function_graph tracer callbacks running in
non-preemptive state. On x86 and powerpc, this is by default, but
on the other architecutres, this will be new.
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/173379653720.973433.18438622234884980494.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Add a few sanity checks to prevent memslot GFNs from ever having alias bits
set.
Like other Coco technologies, TDX has the concept of private and shared
memory. For TDX the private and shared mappings are managed on separate
EPT roots. The private half is managed indirectly though calls into a
protected runtime environment called the TDX module, where the shared half
is managed within KVM in normal page tables.
For TDX, the shared half will be mapped in the higher alias, with a "shared
bit" set in the GPA. However, KVM will still manage it with the same
memslots as the private half. This means memslot looks ups and zapping
operations will be provided with a GFN without the shared bit set.
If these memslot GFNs ever had the bit that selects between the two aliases
it could lead to unexpected behavior in the complicated code that directs
faulting or zapping operations between the roots that map the two aliases.
As a safety measure, prevent memslots from being set at a GFN range that
contains the alias bit.
Also, check in the kvm_faultin_pfn() for the fault path. This later check
does less today, as the alias bits are specifically stripped from the GFN
being checked, however future code could possibly call in to the fault
handler in a way that skips this stripping. Since kvm_faultin_pfn() now
has many references to vcpu->kvm, extract it to local variable.
Link: https://lore.kernel.org/kvm/ZpbKqG_ZhCWxl-Fc@google.com/
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-19-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Don't zap valid mirror roots in kvm_tdp_mmu_zap_all(), which in effect
is only direct roots (invalid and valid).
For TDX, kvm_tdp_mmu_zap_all() is only called during MMU notifier
release. Since, mirrored EPT comes from guest mem, it will never be
mapped to userspace, and won't apply. But in addition to be unnecessary,
mirrored EPT is cleaned up in a special way during VM destruction.
Pass the KVM_INVALID_ROOTS bit into __for_each_tdp_mmu_root_yield_safe()
as well, to clean up invalid direct roots, as is the current behavior.
While at it, remove an obsolete reference to work item-based zapping.
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-18-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Rename kvm_tdp_mmu_invalidate_all_roots() to
kvm_tdp_mmu_invalidate_roots(), and make it enum kvm_tdp_mmu_root_types
as an argument.
kvm_tdp_mmu_invalidate_roots() is called with different root types. For
kvm_mmu_zap_all_fast() it only operates on shared roots. But when tearing
down a VM it needs to invalidate all roots. Have the callers only
invalidate the required roots instead of all roots.
Within kvm_tdp_mmu_invalidate_roots(), respect the root type
passed by checking the root type in root iterator.
Suggested-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-17-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Integrate hooks for mirroring page table operations for cases where TDX
will zap PTEs or free page tables.
Like other Coco technologies, TDX has the concept of private and shared
memory. For TDX the private and shared mappings are managed on separate
EPT roots. The private half is managed indirectly though calls into a
protected runtime environment called the TDX module, where the shared half
is managed within KVM in normal page tables.
Since calls into the TDX module are relatively slow, walking private page
tables by making calls into the TDX module would not be efficient. Because
of this, previous changes have taught the TDP MMU to keep a mirror root,
which is separate, unmapped TDP root that private operations can be
directed to. Currently this root is disconnected from the guest. Now add
plumbing to propagate changes to the "external" page tables being
mirrored. Just create the x86_ops for now, leave plumbing the operations
into the TDX module for future patches.
Add two operations for tearing down page tables, one for freeing page
tables (free_external_spt) and one for zapping PTEs (remove_external_spte).
Define them such that remove_external_spte will perform a TLB flush as
well. (in TDX terms "ensure there are no active translations").
TDX MMU support will exclude certain MMU operations, so only plug in the
mirroring x86 ops where they will be needed. For zapping/freeing, only
hook tdp_mmu_iter_set_spte() which is used for mapping and linking PTs.
Don't bother hooking tdp_mmu_set_spte_atomic() as it is only used for
zapping PTEs in operations unsupported by TDX: zapping collapsible PTEs and
kvm_mmu_zap_all_fast().
In previous changes to address races around concurrent populating using
tdp_mmu_set_spte_atomic(), a solution was introduced to temporarily set
FROZEN_SPTE in the mirrored page tables while performing the external
operations. Such a solution is not needed for the tear down paths in TDX
as these will always be performed with the mmu_lock held for write.
Sprinkle some KVM_BUG_ON()s to reflect this.
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-16-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Integrate hooks for mirroring page table operations for cases where TDX
will set PTEs or link page tables.
Like other Coco technologies, TDX has the concept of private and shared
memory. For TDX the private and shared mappings are managed on separate
EPT roots. The private half is managed indirectly through calls into a
protected runtime environment called the TDX module, where the shared half
is managed within KVM in normal page tables.
Since calls into the TDX module are relatively slow, walking private page
tables by making calls into the TDX module would not be efficient. Because
of this, previous changes have taught the TDP MMU to keep a mirror root,
which is separate, unmapped TDP root that private operations can be
directed to. Currently this root is disconnected from any actual guest
mapping. Now add plumbing to propagate changes to the "external" page
tables being mirrored. Just create the x86_ops for now, leave plumbing the
operations into the TDX module for future patches.
Add two operations for setting up external page tables, one for linking
new page tables and one for setting leaf PTEs. Don't add any op for
configuring the root PFN, as TDX handles this itself. Don't provide a
way to set permissions on the PTEs also, as TDX doesn't support it.
This results in MMU "mirroring" support that is very targeted towards TDX.
Since it is likely there will be no other user, the main benefit of making
the support generic is to keep TDX specific *looking* code outside of the
MMU. As a generic feature it will make enough sense from TDX's
perspective. For developers unfamiliar with TDX arch it can express the
general concepts such that they can continue to work in the code.
TDX MMU support will exclude certain MMU operations, so only plug in the
mirroring x86 ops where they will be needed. For setting/linking, only
hook tdp_mmu_set_spte_atomic() which is used for mapping and linking
PTs. Don't bother hooking tdp_mmu_iter_set_spte() as it is only used for
setting PTEs in operations unsupported by TDX: splitting huge pages and
write protecting. Sprinkle KVM_BUG_ON()s to document as code that these
paths are not supported for mirrored page tables. For zapping operations,
leave those for near future changes.
Many operations in the TDP MMU depend on atomicity of the PTE update.
While the mirror PTE on KVM's side can be updated atomically, the update
that happens inside the external operations (S-EPT updates via TDX module
call) can't happen atomically with the mirror update. The following race
could result during two vCPU's populating private memory:
* vcpu 1: atomically update 2M level mirror EPT entry to be present
* vcpu 2: read 2M level EPT entry that is present
* vcpu 2: walk down into 4K level EPT
* vcpu 2: atomically update 4K level mirror EPT entry to be present
* vcpu 2: set_exterma;_spte() to update 4K secure EPT entry => error
because 2M secure EPT entry is not populated yet
* vcpu 1: link_external_spt() to update 2M secure EPT entry
Prevent this by setting the mirror PTE to FROZEN_SPTE while the reflect
operations are performed. Only write the actual mirror PTE value once the
reflect operations have completed. When trying to set a PTE to present and
encountering a frozen SPTE, retry the fault.
By doing this the race is prevented as follows:
* vcpu 1: atomically update 2M level EPT entry to be FROZEN_SPTE
* vcpu 2: read 2M level EPT entry that is FROZEN_SPTE
* vcpu 2: find that the EPT entry is frozen
abandon page table walk to resume guest execution
* vcpu 1: link_external_spt() to update 2M secure EPT entry
* vcpu 1: atomically update 2M level EPT entry to be present (unfreeze)
* vcpu 2: resume guest execution
Depending on vcpu 1 state, vcpu 2 may result in EPT violation
again or make progress on guest execution
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-15-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
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Teach the MMU notifier callbacks how to check kvm_gfn_range.process to
filter which KVM MMU root types to operate on.
The private GPAs are backed by guest memfd. Such memory is not subjected
to MMU notifier callbacks because it can't be mapped into the host user
address space. Now kvm_gfn_range conveys info about which root to operate
on. Enhance the callback to filter the root page table type.
The KVM MMU notifier comes down to two functions.
kvm_tdp_mmu_unmap_gfn_range() and __kvm_tdp_mmu_age_gfn_range():
- invalidate_range_start() calls kvm_tdp_mmu_unmap_gfn_range()
- invalidate_range_end() doesn't call into arch code
- the other callbacks call __kvm_tdp_mmu_age_gfn_range()
For VM's without a private/shared split in the EPT, all operations
should target the normal(direct) root.
With the switch from for_each_tdp_mmu_root() to
__for_each_tdp_mmu_root() in kvm_tdp_mmu_handle_gfn(), there are no
longer any users of for_each_tdp_mmu_root(). Remove it.
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-14-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Add the ability for the TDP MMU to maintain a mirror of a separate
mapping.
Like other Coco technologies, TDX has the concept of private and shared
memory. For TDX the private and shared mappings are managed on separate
EPT roots. The private half is managed indirectly through calls into a
protected runtime environment called the TDX module, where the shared half
is managed within KVM in normal page tables.
In order to handle both shared and private memory, KVM needs to learn to
handle faults and other operations on the correct root for the operation.
KVM could learn the concept of private roots, and operate on them by
calling out to operations that call into the TDX module. But there are two
problems with that:
1. Calls into the TDX module are relatively slow compared to the simple
accesses required to read a PTE managed directly by KVM.
2. Other Coco technologies deal with private memory completely differently
and it will make the code confusing when being read from their
perspective. Special operations added for TDX that set private or zap
private memory will have nothing to do with these other private memory
technologies. (SEV, etc).
To handle these, instead teach the TDP MMU about a new concept "mirror
roots". Such roots maintain page tables that are not actually mapped,
and are just used to traverse quickly to determine if the mid level page
tables need to be installed. When the memory be mirrored needs to actually
be changed, calls can be made to via x86_ops.
private KVM page fault |
| |
V |
private GPA | CPU protected EPTP
| | |
V | V
mirror PT root | external PT root
| | |
V | V
mirror PT --hook to propagate-->external PT
| | |
\--------------------+------\ |
| | |
| V V
| private guest page
|
|
non-encrypted memory | encrypted memory
|
Leave calling out to actually update the private page tables that are being
mirrored for later changes. Just implement the handling of MMU operations
on to mirrored roots.
In order to direct operations to correct root, add root types
KVM_DIRECT_ROOTS and KVM_MIRROR_ROOTS. Tie the usage of mirrored/direct
roots to private/shared with conditionals. It could also be implemented by
making the kvm_tdp_mmu_root_types and kvm_gfn_range_filter enum bits line
up such that conversion could be a direct assignment with a case. Don't do
this because the mapping of private to mirrored is confusing enough. So it
is worth not hiding the logic in type casting.
Cleanup the mirror root in kvm_mmu_destroy() instead of the normal place
in kvm_mmu_free_roots(), because the private root that is being cannot be
rebuilt like a normal root. It needs to persist for the lifetime of the VM.
The TDX module will also need to be provided with page tables to use for
the actual mapping being mirrored by the mirrored page tables. Allocate
these in the mapping path using the recently added
kvm_mmu_alloc_external_spt().
Don't support 2M page for now. This is avoided by forcing 4k pages in the
fault. Add a KVM_BUG_ON() to verify.
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-13-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Take the root as an argument of tdp_mmu_for_each_pte() instead of looking
it up in the mmu. With no other purpose of passing the mmu, drop it.
Future changes will want to change which root is used based on the context
of the MMU operation. So change the callers to pass in the root currently
used, mmu->root.hpa in a preparatory patch to make the later one smaller
and easier to review.
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-12-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
