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| author |   Vitaly Kuznetsov <vkuznets@redhat.com> | 2018-10-16 18:50:06 +0200 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2018-10-17 00:30:17 +0200 |
| commit | a7c42bb6da6b1b54b2e7bd567636d72d87b10a79 (patch) | |
| tree | 50697d0c76dfff34f090ab30b178ad4bd02f6c06 /arch/x86/kvm | |
| parent | x86/kvm/hyperv: don't clear VP assist pages on init (diff) | |
| download | linux-dev-a7c42bb6da6b1b54b2e7bd567636d72d87b10a79.tar.xz linux-dev-a7c42bb6da6b1b54b2e7bd567636d72d87b10a79.zip | |
x86/kvm/lapic: preserve gfn_to_hva_cache len on cache reinit
vcpu->arch.pv_eoi is accessible through both HV_X64_MSR_VP_ASSIST_PAGE and
MSR_KVM_PV_EOI_EN so on migration userspace may try to restore them in any
order. Values match, however, kvm_lapic_enable_pv_eoi() uses different
length: for Hyper-V case it's the whole struct hv_vp_assist_page, for KVM
native case it is 8. In case we restore KVM-native MSR last cache will
be reinitialized with len=8 so trying to access VP assist page beyond
8 bytes with kvm_read_guest_cached() will fail.
Check if we re-initializing cache for the same address and preserve length
in case it was greater.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 79358fd6a71c..3cd227ff807f 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2647,14 +2647,22 @@ int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data) int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned long len) { u64 addr = data & ~KVM_MSR_ENABLED; + struct gfn_to_hva_cache *ghc = &vcpu->arch.pv_eoi.data; + unsigned long new_len; + if (!IS_ALIGNED(addr, 4)) return 1; vcpu->arch.pv_eoi.msr_val = data; if (!pv_eoi_enabled(vcpu)) return 0; - return kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.pv_eoi.data, - addr, len); + + if (addr == ghc->gpa && len <= ghc->len) + new_len = ghc->len; + else + new_len = len; + + return kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, addr, new_len); } void kvm_apic_accept_events(struct kvm_vcpu *vcpu) |