From 8f8292a0ebaf2d45c97c30a99b116a92a146394b Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 8 Nov 2021 16:28:19 +0100 Subject: [PATCH] KVM: x86: Don't update vcpu->arch.pv_eoi.msr_val when a bogus value was written to MSR_KVM_PV_EOI_EN When kvm_gfn_to_hva_cache_init() call from kvm_lapic_set_pv_eoi() fails, MSR write to MSR_KVM_PV_EOI_EN results in #GP so it is reasonable to expect that the value we keep internally in KVM wasn't updated. Signed-off-by: Vitaly Kuznetsov Message-Id: <20211108152819.12485-3-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/lapic.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 3573b50d9036a..4388d22df5002 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2857,20 +2857,25 @@ int kvm_lapic_set_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; + int ret; if (!IS_ALIGNED(addr, 4)) return 1; - vcpu->arch.pv_eoi.msr_val = data; - if (!pv_eoi_enabled(vcpu)) - return 0; + if (data & KVM_MSR_ENABLED) { + if (addr == ghc->gpa && len <= ghc->len) + new_len = ghc->len; + else + new_len = len; - if (addr == ghc->gpa && len <= ghc->len) - new_len = ghc->len; - else - new_len = len; + ret = kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, addr, new_len); + if (ret) + return ret; + } + + vcpu->arch.pv_eoi.msr_val = data; - return kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, addr, new_len); + return 0; } int kvm_apic_accept_events(struct kvm_vcpu *vcpu) -- 2.39.5