Limiting exposed Hyper-V features requires a fast way to check if the
particular feature is exposed in guest visible CPUIDs or not. To aboid
looping through all CPUID entries on every hypercall/MSR access cache
the required leaves on CPUID update.
Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 8 ++++++
arch/x86/kvm/hyperv.c | 49 ++++++++++++++++++++++++++-------
2 files changed, 47 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index dc40897c41bc..6525d2716b09 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -531,6 +531,14 @@ struct kvm_vcpu_hv {
DECLARE_BITMAP(stimer_pending_bitmap, HV_SYNIC_STIMER_COUNT);
cpumask_t tlb_flush;
bool enforce_cpuid;
+ struct {
+ u32 features_eax; /* HYPERV_CPUID_FEATURES.EAX */
+ u32 features_ebx; /* HYPERV_CPUID_FEATURES.EBX */
+ u32 features_edx; /* HYPERV_CPUID_FEATURES.EDX */
+ u32 enlightenments_eax; /* HYPERV_CPUID_ENLIGHTMENT_INFO.EAX */
+ u32 enlightenments_ebx; /* HYPERV_CPUID_ENLIGHTMENT_INFO.EBX */
+ u32 syndbg_cap_eax; /*
HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES.EAX */
+ } cpuid_cache;
};
/* Xen HVM per vcpu emulation context */
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 557897c453a9..ccb298cfc933 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -273,15 +273,10 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
static bool kvm_hv_is_syndbg_enabled(struct kvm_vcpu *vcpu)
{
- struct kvm_cpuid_entry2 *entry;
-
- entry = kvm_find_cpuid_entry(vcpu,
- HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES,
- 0);
- if (!entry)
- return false;
+ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
- return entry->eax & HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
+ return hv_vcpu->cpuid_cache.syndbg_cap_eax &
+ HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
}
static int kvm_hv_syndbg_complete_userspace(struct kvm_vcpu *vcpu)
@@ -1801,12 +1796,46 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, u64
ingpa, u64 outgpa,
void kvm_hv_set_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *entry;
+ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_INTERFACE, 0);
- if (entry && entry->eax == HYPERV_CPUID_SIGNATURE_EAX)
+ if (entry && entry->eax == HYPERV_CPUID_SIGNATURE_EAX) {
vcpu->arch.hyperv_enabled = true;
- else
+ } else {
vcpu->arch.hyperv_enabled = false;
+ return;
+ }
+
+ if (!to_hv_vcpu(vcpu) && kvm_hv_vcpu_init(vcpu))
+ return;
+
+ hv_vcpu = to_hv_vcpu(vcpu);
+
+ entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_FEATURES, 0);
+ if (entry) {
+ hv_vcpu->cpuid_cache.features_eax = entry->eax;
+ hv_vcpu->cpuid_cache.features_ebx = entry->ebx;
+ hv_vcpu->cpuid_cache.features_edx = entry->edx;
+ } else {
+ hv_vcpu->cpuid_cache.features_eax = 0;
+ hv_vcpu->cpuid_cache.features_ebx = 0;
+ hv_vcpu->cpuid_cache.features_edx = 0;
+ }
+
+ entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_ENLIGHTMENT_INFO, 0);
+ if (entry) {
+ hv_vcpu->cpuid_cache.enlightenments_eax = entry->eax;
+ hv_vcpu->cpuid_cache.enlightenments_ebx = entry->ebx;
+ } else {
+ hv_vcpu->cpuid_cache.enlightenments_eax = 0;
+ hv_vcpu->cpuid_cache.enlightenments_ebx = 0;
+ }
+
+ entry = kvm_find_cpuid_entry(vcpu,
HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES, 0);
+ if (entry)
+ hv_vcpu->cpuid_cache.syndbg_cap_eax = entry->eax;
+ else
+ hv_vcpu->cpuid_cache.syndbg_cap_eax = 0;
}
int kvm_hv_set_enforce_cpuid(struct kvm_vcpu *vcpu, bool enforce)
--
2.30.2
