4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Bonzini pbonzini@redhat.com
commit 44883f01fe6ae436a8604c47d8435276fef369b0 upstream.
Some of the MSRs returned by GET_MSR_INDEX_LIST currently cannot be sent back to KVM_GET_MSR and/or KVM_SET_MSR; either they can never be sent back, or you they are only accepted under special conditions. This makes the API a pain to use.
To avoid this pain, this patch makes it so that the result of the get-list ioctl can always be used for host-initiated get and set. Since we don't have a separate way to check for read-only MSRs, this means some Hyper-V MSRs are ignored when written. Arguably they should not even be in the result of GET_MSR_INDEX_LIST, but I am leaving there in case userspace is using the outcome of GET_MSR_INDEX_LIST to derive the support for the corresponding Hyper-V feature.
Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/hyperv.c | 27 ++++++++++++++++++++------- arch/x86/kvm/hyperv.h | 2 +- arch/x86/kvm/x86.c | 15 +++++++++------ 3 files changed, 30 insertions(+), 14 deletions(-)
--- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -235,7 +235,7 @@ static int synic_set_msr(struct kvm_vcpu struct kvm_vcpu *vcpu = synic_to_vcpu(synic); int ret;
- if (!synic->active) + if (!synic->active && !host) return 1;
trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host); @@ -295,11 +295,12 @@ static int synic_set_msr(struct kvm_vcpu return ret; }
-static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata) +static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata, + bool host) { int ret;
- if (!synic->active) + if (!synic->active && !host) return 1;
ret = 0; @@ -1014,6 +1015,11 @@ static int kvm_hv_set_msr_pw(struct kvm_ case HV_X64_MSR_TSC_EMULATION_STATUS: hv->hv_tsc_emulation_status = data; break; + case HV_X64_MSR_TIME_REF_COUNT: + /* read-only, but still ignore it if host-initiated */ + if (!host) + return 1; + break; default: vcpu_unimpl(vcpu, "Hyper-V uhandled wrmsr: 0x%x data 0x%llx\n", msr, data); @@ -1101,6 +1107,12 @@ static int kvm_hv_set_msr(struct kvm_vcp return stimer_set_count(vcpu_to_stimer(vcpu, timer_index), data, host); } + case HV_X64_MSR_TSC_FREQUENCY: + case HV_X64_MSR_APIC_FREQUENCY: + /* read-only, but still ignore it if host-initiated */ + if (!host) + return 1; + break; default: vcpu_unimpl(vcpu, "Hyper-V uhandled wrmsr: 0x%x data 0x%llx\n", msr, data); @@ -1156,7 +1168,8 @@ static int kvm_hv_get_msr_pw(struct kvm_ return 0; }
-static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) +static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, + bool host) { u64 data = 0; struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv; @@ -1183,7 +1196,7 @@ static int kvm_hv_get_msr(struct kvm_vcp case HV_X64_MSR_SIMP: case HV_X64_MSR_EOM: case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15: - return synic_get_msr(vcpu_to_synic(vcpu), msr, pdata); + return synic_get_msr(vcpu_to_synic(vcpu), msr, pdata, host); case HV_X64_MSR_STIMER0_CONFIG: case HV_X64_MSR_STIMER1_CONFIG: case HV_X64_MSR_STIMER2_CONFIG: @@ -1229,7 +1242,7 @@ int kvm_hv_set_msr_common(struct kvm_vcp return kvm_hv_set_msr(vcpu, msr, data, host); }
-int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) +int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) { if (kvm_hv_msr_partition_wide(msr)) { int r; @@ -1239,7 +1252,7 @@ int kvm_hv_get_msr_common(struct kvm_vcp mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock); return r; } else - return kvm_hv_get_msr(vcpu, msr, pdata); + return kvm_hv_get_msr(vcpu, msr, pdata, host); }
static __always_inline int get_sparse_bank_no(u64 valid_bank_mask, int bank_no) --- a/arch/x86/kvm/hyperv.h +++ b/arch/x86/kvm/hyperv.h @@ -48,7 +48,7 @@ static inline struct kvm_vcpu *synic_to_ }
int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host); -int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata); +int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host);
bool kvm_hv_hypercall_enabled(struct kvm *kvm); int kvm_hv_hypercall(struct kvm_vcpu *vcpu); --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2185,10 +2185,11 @@ static int set_msr_mce(struct kvm_vcpu * vcpu->arch.mcg_status = data; break; case MSR_IA32_MCG_CTL: - if (!(mcg_cap & MCG_CTL_P)) + if (!(mcg_cap & MCG_CTL_P) && + (data || !msr_info->host_initiated)) return 1; if (data != 0 && data != ~(u64)0) - return -1; + return 1; vcpu->arch.mcg_ctl = data; break; default: @@ -2576,7 +2577,7 @@ int kvm_get_msr(struct kvm_vcpu *vcpu, s } EXPORT_SYMBOL_GPL(kvm_get_msr);
-static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) +static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) { u64 data; u64 mcg_cap = vcpu->arch.mcg_cap; @@ -2591,7 +2592,7 @@ static int get_msr_mce(struct kvm_vcpu * data = vcpu->arch.mcg_cap; break; case MSR_IA32_MCG_CTL: - if (!(mcg_cap & MCG_CTL_P)) + if (!(mcg_cap & MCG_CTL_P) && !host) return 1; data = vcpu->arch.mcg_ctl; break; @@ -2724,7 +2725,8 @@ int kvm_get_msr_common(struct kvm_vcpu * case MSR_IA32_MCG_CTL: case MSR_IA32_MCG_STATUS: case MSR_IA32_MC0_CTL ... MSR_IA32_MCx_CTL(KVM_MAX_MCE_BANKS) - 1: - return get_msr_mce(vcpu, msr_info->index, &msr_info->data); + return get_msr_mce(vcpu, msr_info->index, &msr_info->data, + msr_info->host_initiated); case MSR_K7_CLK_CTL: /* * Provide expected ramp-up count for K7. All other @@ -2745,7 +2747,8 @@ int kvm_get_msr_common(struct kvm_vcpu * case HV_X64_MSR_TSC_EMULATION_CONTROL: case HV_X64_MSR_TSC_EMULATION_STATUS: return kvm_hv_get_msr_common(vcpu, - msr_info->index, &msr_info->data); + msr_info->index, &msr_info->data, + msr_info->host_initiated); break; case MSR_IA32_BBL_CR_CTL3: /* This legacy MSR exists but isn't fully documented in current