From afe0eb5a82f6eb20fbe342a70454f49ca226a703 Mon Sep 17 00:00:00 2001 From: Joao Martins Date: Wed, 13 Jun 2018 06:10:37 -0400 Subject: [PATCH] KVM: x86/xen: fix Xen hypercall page msr handling Xen usually places its MSR at 0x40000000 or 0x40000200 depending on whether it is running in viridian mode or not. Note that this is not ABI guaranteed, so it is possible for Xen to advertise the MSR some place else. Given the way xen_hvm_config() is handled, if the former address is selected, this will conflict with Hyper-V's MSR (HV_X64_MSR_GUEST_OS_ID) which unconditionally uses the same address. Given that the MSR location is arbitrary, move the xen_hvm_config() handling to the top of kvm_set_msr_common() before falling through. Signed-off-by: Joao Martins Signed-off-by: David Woodhouse --- arch/x86/kvm/x86.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a480804ae27a3..c0c3a904080f0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3007,6 +3007,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) u32 msr = msr_info->index; u64 data = msr_info->data; + if (msr && msr == vcpu->kvm->arch.xen_hvm_config.msr) + return xen_hvm_config(vcpu, data); + switch (msr) { case MSR_AMD64_NB_CFG: case MSR_IA32_UCODE_WRITE: @@ -3294,8 +3297,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) vcpu->arch.msr_misc_features_enables = data; break; default: - if (msr && (msr == vcpu->kvm->arch.xen_hvm_config.msr)) - return xen_hvm_config(vcpu, data); if (kvm_pmu_is_valid_msr(vcpu, msr)) return kvm_pmu_set_msr(vcpu, msr_info); return KVM_MSR_RET_INVALID; -- 2.50.1