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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-12 10:17:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-12 10:17:16 -0700 |
| commit | 4f8a3cc1183c442daee6cc65360e3385021131e4 (patch) | |
| tree | 030efd9b19604201a4a42e10dd44357e5c2de1bd /arch/x86/kvm/x86.c | |
| parent | 0785249f8b93836986e9d1bdeefd2a2c13f160af (diff) | |
| parent | e6f8b6c12f03818baacc5f504fe83fa5e20771d6 (diff) | |
| download | linux-4f8a3cc1183c442daee6cc65360e3385021131e4.tar.gz linux-4f8a3cc1183c442daee6cc65360e3385021131e4.tar.xz | |
Merge tag 'x86-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
"A set of three patches to fix the fallout of the newly added split
lock detection feature.
It addressed the case where a KVM guest triggers a split lock #AC and
KVM reinjects it into the guest which is not prepared to handle it.
Add proper sanity checks which prevent the unconditional injection
into the guest and handles the #AC on the host side in the same way as
user space detections are handled. Depending on the detection mode it
either warns and disables detection for the task or kills the task if
the mode is set to fatal"
* tag 'x86-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest
KVM: x86: Emulate split-lock access as a write in emulator
x86/split_lock: Provide handle_guest_split_lock()
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 027dfd278a97..3bf2ecafd027 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5839,6 +5839,7 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, { struct kvm_host_map map; struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); + u64 page_line_mask; gpa_t gpa; char *kaddr; bool exchanged; @@ -5853,7 +5854,16 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE) goto emul_write; - if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK)) + /* + * Emulate the atomic as a straight write to avoid #AC if SLD is + * enabled in the host and the access splits a cache line. + */ + if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) + page_line_mask = ~(cache_line_size() - 1); + else + page_line_mask = PAGE_MASK; + + if (((gpa + bytes - 1) & page_line_mask) != (gpa & page_line_mask)) goto emul_write; if (kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), &map)) |