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 <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
This commit is contained in:
Joao Martins 2018-06-13 06:10:37 -04:00 committed by David Woodhouse
parent a2855afc7e
commit 1232f8e6c9
1 changed files with 3 additions and 2 deletions

View File

@ -3029,6 +3029,9 @@ 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:
@ -3304,8 +3307,6 @@ 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;