kernel/linux.git/arch/x86, branch v6.3.2

x86/ioapic: Don't return 0 from arch_dynirq_lower_bound()

2023-05-11T14:17:09+00:00

[ Upstream commit 5af507bef93c09a94fb8f058213b489178f4cbe5 ] arch_dynirq_lower_bound() is invoked by the core interrupt code to retrieve the lowest possible Linux interrupt number for dynamically allocated interrupts like MSI. The x86 implementation uses this to exclude the IO/APIC GSI space. This works correctly as long as there is an IO/APIC registered, but returns 0 if not. This has been observed in VMs where the BIOS does not advertise an IO/APIC. 0 is an invalid interrupt number except for the legacy timer interrupt on x86. The return value is unchecked in the core code, so it ends up to allocate interrupt number 0 which is subsequently considered to be invalid by the caller, e.g. the MSI allocation code. The function has already a check for 0 in the case that an IO/APIC is registered, as ioapic_dynirq_base is 0 in case of device tree setups. Consolidate this and zero check for both ioapic_dynirq_base and gsi_top, which is used in the case that no IO/APIC is registered. Fixes: 3e5bedc2c258 ("x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machines") Signed-off-by: Saurabh Sengar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/1679988604-20308-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Sasha Levin

x86/apic: Fix atomic update of offset in reserve_eilvt_offset()

2023-05-11T14:17:06+00:00

[ Upstream commit f96fb2df3eb31ede1b34b0521560967310267750 ] The detection of atomic update failure in reserve_eilvt_offset() is not correct. The value returned by atomic_cmpxchg() should be compared to the old value from the location to be updated. If these two are the same, then atomic update succeeded and "eilvt_offsets[offset]" location is updated to "new" in an atomic way. Otherwise, the atomic update failed and it should be retried with the value from "eilvt_offsets[offset]" - exactly what atomic_try_cmpxchg() does in a correct and more optimal way. Fixes: a68c439b1966c ("apic, x86: Check if EILVT APIC registers are available (AMD only)") Signed-off-by: Uros Bizjak Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230227160917.107820-1-ubizjak@gmail.com Signed-off-by: Sasha Levin

x86/MCE/AMD: Use an u64 for bank_map

2023-05-11T14:17:02+00:00

[ Upstream commit 4c1cdec319b9aadb65737c3eb1f5cb74bd6aa156 ] Thee maximum number of MCA banks is 64 (MAX_NR_BANKS), see a0bc32b3cacf ("x86/mce: Increase maximum number of banks to 64"). However, the bank_map which contains a bitfield of which banks to initialize is of type unsigned int and that overflows when those bit numbers are >= 32, leading to UBSAN complaining correctly: UBSAN: shift-out-of-bounds in arch/x86/kernel/cpu/mce/amd.c:1365:38 shift exponent 32 is too large for 32-bit type 'int' Change the bank_map to a u64 and use the proper BIT_ULL() macro when modifying bits in there. [ bp: Rewrite commit message. ] Fixes: a0bc32b3cacf ("x86/mce: Increase maximum number of banks to 64") Signed-off-by: Muralidhara M K Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230127151601.1068324-1-muralimk@amd.com Signed-off-by: Sasha Levin

KVM: x86: Preserve TDP MMU roots until they are explicitly invalidated

2023-05-11T14:16:51+00:00

commit edbdb43fc96b11b3bfa531be306a1993d9fe89ec upstream. Preserve TDP MMU roots until they are explicitly invalidated by gifting the TDP MMU itself a reference to a root when it is allocated. Keeping a reference in the TDP MMU fixes a flaw where the TDP MMU exhibits terrible performance, and can potentially even soft-hang a vCPU, if a vCPU frequently unloads its roots, e.g. when KVM is emulating SMI+RSM. When KVM emulates something that invalidates _all_ TLB entries, e.g. SMI and RSM, KVM unloads all of the vCPUs roots (KVM keeps a small per-vCPU cache of previous roots). Unloading roots is a simple way to ensure KVM flushes and synchronizes all roots for the vCPU, as KVM flushes and syncs when allocating a "new" root (from the vCPU's perspective). In the shadow MMU, KVM keeps track of all shadow pages, roots included, in a per-VM hash table. Unloading a shadow MMU root just wipes it from the per-vCPU cache; the root is still tracked in the per-VM hash table. When KVM loads a "new" root for the vCPU, KVM will find the old, unloaded root in the per-VM hash table. Unlike the shadow MMU, the TDP MMU doesn't track "inactive" roots in a per-VM structure, where "active" in this case means a root is either in-use or cached as a previous root by at least one vCPU. When a TDP MMU root becomes inactive, i.e. the last vCPU reference to the root is put, KVM immediately frees the root (asterisk on "immediately" as the actual freeing may be done by a worker, but for all intents and purposes the root is gone). The TDP MMU behavior is especially problematic for 1-vCPU setups, as unloading all roots effectively frees all roots. The issue is mitigated to some degree in multi-vCPU setups as a different vCPU usually holds a reference to an unloaded root and thus keeps the root alive, allowing the vCPU to reuse its old root after unloading (with a flush+sync). The TDP MMU flaw has been known for some time, as until very recently, KVM's handling of CR0.WP also triggered unloading of all roots. The CR0.WP toggling scenario was eventually addressed by not unloading roots when _only_ CR0.WP is toggled, but such an approach doesn't Just Work for emulating SMM as KVM must emulate a full TLB flush on entry and exit to/from SMM. Given that the shadow MMU plays nice with unloading roots at will, teaching the TDP MMU to do the same is far less complex than modifying KVM to track which roots need to be flushed before reuse. Note, preserving all possible TDP MMU roots is not a concern with respect to memory consumption. Now that the role for direct MMUs doesn't include information about the guest, e.g. CR0.PG, CR0.WP, CR4.SMEP, etc., there are _at most_ six possible roots (where "guest_mode" here means L2): 1. 4-level !SMM !guest_mode 2. 4-level SMM !guest_mode 3. 5-level !SMM !guest_mode 4. 5-level SMM !guest_mode 5. 4-level !SMM guest_mode 6. 5-level !SMM guest_mode And because each vCPU can track 4 valid roots, a VM can already have all 6 root combinations live at any given time. Not to mention that, in practice, no sane VMM will advertise different guest.MAXPHYADDR values across vCPUs, i.e. KVM won't ever use both 4-level and 5-level roots for a single VM. Furthermore, the vast majority of modern hypervisors will utilize EPT/NPT when available, thus the guest_mode=%true cases are also unlikely to be utilized. Reported-by: Jeremi Piotrowski Link: https://lore.kernel.org/all/959c5bce-beb5-b463-7158-33fc4a4f910c@linux.microsoft.com Link: https://lkml.kernel.org/r/20220209170020.1775368-1-pbonzini%40redhat.com Link: https://lore.kernel.org/all/20230322013731.102955-1-minipli@grsecurity.net Link: https://lore.kernel.org/all/000000000000a0bc2b05f9dd7fab@google.com Link: https://lore.kernel.org/all/000000000000eca0b905fa0f7756@google.com Cc: Ben Gardon Cc: David Matlack Cc: stable@vger.kernel.org Tested-by: Jeremi Piotrowski Link: https://lore.kernel.org/r/20230426220323.3079789-1-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nVMX: Emulate NOPs in L2, and PAUSE if it's not intercepted

2023-05-11T14:16:51+00:00

commit 4984563823f0034d3533854c1b50e729f5191089 upstream. Extend VMX's nested intercept logic for emulated instructions to handle "pause" interception, in quotes because KVM's emulator doesn't filter out NOPs when checking for nested intercepts. Failure to allow emulation of NOPs results in KVM injecting a #UD into L2 on any NOP that collides with the emulator's definition of PAUSE, i.e. on all single-byte NOPs. For PAUSE itself, honor L1's PAUSE-exiting control, but ignore PLE to avoid unnecessarily injecting a #UD into L2. Per the SDM, the first execution of PAUSE after VM-Entry is treated as the beginning of a new loop, i.e. will never trigger a PLE VM-Exit, and so L1 can't expect any given execution of PAUSE to deterministically exit. ... the processor considers this execution to be the first execution of PAUSE in a loop. (It also does so for the first execution of PAUSE at CPL 0 after VM entry.) All that said, the PLE side of things is currently a moot point, as KVM doesn't expose PLE to L1. Note, vmx_check_intercept() is still wildly broken when L1 wants to intercept an instruction, as KVM injects a #UD instead of synthesizing a nested VM-Exit. That issue extends far beyond NOP/PAUSE and needs far more effort to fix, i.e. is a problem for the future. Fixes: 07721feee46b ("KVM: nVMX: Don't emulate instructions in guest mode") Cc: Mathias Krause Cc: stable@vger.kernel.org Reviewed-by: Paolo Bonzini Link: https://lore.kernel.org/r/20230405002359.418138-1-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: x86/pmu: Disallow legacy LBRs if architectural LBRs are available

2023-05-11T14:16:50+00:00

commit 098f4c061ea10b777033b71c10bd9fd706820ee9 upstream. Disallow enabling LBR support if the CPU supports architectural LBRs. Traditional LBR support is absent on CPU models that have architectural LBRs, and KVM doesn't yet support arch LBRs, i.e. KVM will pass through non-existent MSRs if userspace enables LBRs for the guest. Cc: stable@vger.kernel.org Cc: Yang Weijiang Cc: Like Xu Reported-by: Paolo Bonzini Fixes: be635e34c284 ("KVM: vmx/pmu: Expose LBR_FMT in the MSR_IA32_PERF_CAPABILITIES") Tested-by: Like Xu Link: https://lore.kernel.org/r/20230128001427.2548858-1-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

x86/alternatives: Do not use integer constant suffixes in inline asm

2023-04-18T09:57:18+00:00

The usage of the BIT() macro in inline asm code was introduced in 6.3 by the commit in the Fixes tag. However, this macro uses "1UL" for integer constant suffixes in its shift operation, while gas before 2.28 does not support the "L" suffix after a number, and gas before 2.27 does not support the "U" suffix, resulting in build errors such as the following with such versions: ./arch/x86/include/asm/uaccess_64.h:124: Error: found 'L', expected: ')' ./arch/x86/include/asm/uaccess_64.h:124: Error: junk at end of line, first unrecognized character is `L' However, the currently minimal binutils version the kernel supports is 2.25. There's a single use of this macro here, revert to (1 << 0) that works with such older binutils. As an additional info, the binutils PRs which add support for those suffixes are: https://sourceware.org/bugzilla/show_bug.cgi?id=19910 https://sourceware.org/bugzilla/show_bug.cgi?id=20732 [ bp: Massage and extend commit message. ] Fixes: 5d1dd961e743 ("x86/alternatives: Add alt_instr.flags") Signed-off-by: Willy Tarreau Signed-off-by: Borislav Petkov (AMD) Tested-by: Jingbo Xu Link: https://lore.kernel.org/lkml/a9aae568-3046-306c-bd71-92c1fc8eeddc@linux.alibaba.com/

Merge tag 'x86_urgent_for_v6.3_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-04-16T17:28:29+00:00

Pull x86 fix from Borislav Petkov: - Drop __init annotation from two rtc functions which get called after boot is done, in order to prevent a crash * tag 'x86_urgent_for_v6.3_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/rtc: Remove __init for runtime functions

Merge tag 'kbuild-fixes-v6.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2023-04-16T16:46:32+00:00

Pull Kbuild fixes from Masahiro Yamada: - Drop debug info from purgatory objects again - Document that kernel.org provides prebuilt LLVM toolchains - Give up handling untracked files for source package builds - Avoid creating corrupted cpio when KBUILD_BUILD_TIMESTAMP is given with a pre-epoch data. - Change panic_show_mem() to a macro to handle variable-length argument - Compress tarballs on-the-fly again * tag 'kbuild-fixes-v6.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: do not create intermediate *.tar for tar packages kbuild: do not create intermediate *.tar for source tarballs kbuild: merge cmd_archive_linux and cmd_archive_perf init/initramfs: Fix argument forwarding to panic() in panic_show_mem() initramfs: Check negative timestamp to prevent broken cpio archive kbuild: give up untracked files for source package builds Documentation/llvm: Add a note about prebuilt kernel.org toolchains purgatory: fix disabling debug info

x86/rtc: Remove __init for runtime functions

2023-04-13T12:41:04+00:00

set_rtc_noop(), get_rtc_noop() are after booting, therefore their __init annotation is wrong. A crash was observed on an x86 platform where CMOS RTC is unused and disabled via device tree. set_rtc_noop() was invoked from ntp: sync_hw_clock(), although CONFIG_RTC_SYSTOHC=n, however sync_cmos_clock() doesn't honour that. Workqueue: events_power_efficient sync_hw_clock RIP: 0010:set_rtc_noop Call Trace: update_persistent_clock64 sync_hw_clock Fix this by dropping the __init annotation from set/get_rtc_noop(). Fixes: c311ed6183f4 ("x86/init: Allow DT configured systems to disable RTC at boot time") Signed-off-by: Matija Glavinic Pecotic Signed-off-by: Thomas Gleixner Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/59f7ceb1-446b-1d3d-0bc8-1f0ee94b1e18@nokia.com