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Subject[PATCH] KVM: x86: Add Intel CPUID.1F cpuid emulation support
Date
Expose Intel V2 Extended Topology Enumeration Leaf to guest only when
host system has multiple software-visible die within each package.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
arch/x86/kvm/cpuid.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index fd39516..9fc14f2 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -65,6 +65,16 @@ u64 kvm_supported_xcr0(void)
return xcr0;
}

+/* We need to check if the host cpu has multi-chip packaging technology. */
+static bool kvm_supported_intel_mcp(void)
+{
+ u32 eax, ignored;
+
+ cpuid_count(0x1f, 0, &eax, &ignored, &ignored, &ignored);
+
+ return boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && (eax != 0);
+}
+
#define F(x) bit(X86_FEATURE_##x)

int kvm_update_cpuid(struct kvm_vcpu *vcpu)
@@ -426,6 +436,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
switch (function) {
case 0:
entry->eax = min(entry->eax, (u32)(f_intel_pt ? 0x14 : 0xd));
+ entry->eax = kvm_supported_intel_mcp() ? 0x1f : entry->eax;
break;
case 1:
entry->edx &= kvm_cpuid_1_edx_x86_features;
@@ -544,6 +555,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
entry->edx = edx.full;
break;
}
+ /* function 0x1f has additional index. */
+ case 0x1f:
/* function 0xb has additional index. */
case 0xb: {
int i, level_type;
--
1.8.3.1
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