This is a note to let you know that I've just added the patch titled
KVM: x86: do not report preemption if the steal time cache is stale
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-do-not-report-preemption-if-the-steal-time-cache-is-stale.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable-owner@xxxxxxxxxxxxxxx Wed May 10 20:16:28 2023
From: Rishabh Bhatnagar <risbhat@xxxxxxxxxx>
Date: Wed, 10 May 2023 18:15:46 +0000
Subject: KVM: x86: do not report preemption if the steal time cache is stale
To: <gregkh@xxxxxxxxxxxxxxxxxxx>, <stable@xxxxxxxxxxxxxxx>
Cc: <lee@xxxxxxxxxx>, <seanjc@xxxxxxxxxx>, <kvm@xxxxxxxxxxxxxxx>, <bp@xxxxxxxxx>, <mingo@xxxxxxxxxx>, <tglx@xxxxxxxxxxxxx>, <pbonzini@xxxxxxxxxx>, <vkuznets@xxxxxxxxxx>, <wanpengli@xxxxxxxxxxx>, <jmattson@xxxxxxxxxx>, <joro@xxxxxxxxxx>, David Woodhouse <dwmw@xxxxxxxxxxxx>, Rishabh Bhatnagar <risbhat@xxxxxxxxxx>, Allen Pais <apais@xxxxxxxxxxxxxxxxxxx>
Message-ID: <20230510181547.22451-9-risbhat@xxxxxxxxxx>
From: Rishabh Bhatnagar <risbhat@xxxxxxxxxx>
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
commit c3c28d24d910a746b02f496d190e0e8c6560224b upstream.
Commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time
/ preempted status", 2021-11-11) open coded the previous call to
kvm_map_gfn, but in doing so it dropped the comparison between the cached
guest physical address and the one in the MSR. This cause an incorrect
cache hit if the guest modifies the steal time address while the memslots
remain the same. This can happen with kexec, in which case the preempted
bit is written at the address used by the old kernel instead of
the old one.
Cc: David Woodhouse <dwmw@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status")
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Rishabh Bhatnagar <risbhat@xxxxxxxxxx>
Tested-by: Allen Pais <apais@xxxxxxxxxxxxxxxxxxx>
Acked-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4096,6 +4096,7 @@ static void kvm_steal_time_set_preempted
struct kvm_steal_time __user *st;
struct kvm_memslots *slots;
static const u8 preempted = KVM_VCPU_PREEMPTED;
+ gpa_t gpa = vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS;
/*
* The vCPU can be marked preempted if and only if the VM-Exit was on
@@ -4123,6 +4124,7 @@ static void kvm_steal_time_set_preempted
slots = kvm_memslots(vcpu->kvm);
if (unlikely(slots->generation != ghc->generation ||
+ gpa != ghc->gpa ||
kvm_is_error_hva(ghc->hva) || !ghc->memslot))
return;
Patches currently in stable-queue which might be from stable-owner@xxxxxxxxxxxxxxx are
queue-5.10/kvm-fix-steal-time-asm-constraints.patch
queue-5.10/kvm-x86-ensure-pv-tlb-flush-tracepoint-reflects-kvm-behavior.patch
queue-5.10/blk-crypto-make-blk_crypto_evict_key-more-robust.patch
queue-5.10/kvm-x86-do-not-report-preemption-if-the-steal-time-cache-is-stale.patch
queue-5.10/kvm-x86-do-not-set-st-preempted-when-going-back-to-user-space.patch
queue-5.10/kvm-x86-move-guest_pv_has-out-of-user_access-section.patch
queue-5.10/kvm-x86-fix-recording-of-guest-steal-time-preempted-status.patch
queue-5.10/blk-mq-release-crypto-keyslot-before-reporting-i-o-complete.patch
queue-5.10/kvm-x86-revalidate-steal-time-cache-if-msr-value-changes.patch
queue-5.10/blk-crypto-make-blk_crypto_evict_key-return-void.patch
queue-5.10/kvm-x86-remove-obsolete-disabling-of-page-faults-in-kvm_arch_vcpu_put.patch
