[PATCH 21/26] KVM: x86: Handle RDTSCP CPUID adjustment in VMX code

Sean Christopherson
2020-01-29T23:47:06Z

Move the clearing of the RDTSCP CPUID bit into VMX, which has a separate
VMCS control to enable RDTSCP in non-root, to eliminate an instance of
the undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in the
common CPUID handling code. Drop ->rdtscp_supported() since CPUID
adjustment was the last remaining user.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/kvm_host.h | 1 -
arch/x86/kvm/cpuid.c | 3 +--
arch/x86/kvm/svm.c | 6 ------
arch/x86/kvm/vmx/vmx.c | 6 ++++--
4 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8a685509c218..3cd11257257c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1144,7 +1144,6 @@ struct kvm_x86_ops {
int (*get_tdp_level)(struct kvm_vcpu *vcpu);
u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
int (*get_lpage_level)(void);
- bool (*rdtscp_supported)(void);

void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e376d648f94d..ce7f6dfcf832 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -410,7 +410,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
unsigned f_gbpages = 0;
unsigned f_lm = 0;
#endif
- unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;

@@ -432,7 +431,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
F(PAT) | F(PSE36) | 0 /* Reserved */ |
f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
- F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
+ F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) |
0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
/* cpuid 1.ecx */
const u32 kvm_cpuid_1_ecx_x86_features =
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1092d5e6c683..2adc3a474b80 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6096,11 +6096,6 @@ static int svm_get_lpage_level(void)
return PT_PDPE_LEVEL;
}

-static bool svm_rdtscp_supported(void)
-{
- return boot_cpu_has(X86_FEATURE_RDTSCP);
-}
-
static bool svm_xsaves_supported(void)
{
return boot_cpu_has(X86_FEATURE_XSAVES);
@@ -7476,7 +7471,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {

.cpuid_update = svm_cpuid_update,

- .rdtscp_supported = svm_rdtscp_supported,
.xsaves_supported = svm_xsaves_supported,
.umip_emulated = svm_umip_emulated,
.pt_supported = svm_pt_supported,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 3845ca7da6e0..f244b2356847 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7145,6 +7145,10 @@ static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
if (vmx_umip_emulated())
cpuid_entry_set(entry, X86_FEATURE_UMIP);
break;
+ case 0x80000001:
+ if (!cpu_has_vmx_rdtscp())
+ cpuid_entry_clear(entry, X86_FEATURE_RDTSCP);
+ break;
default:
break;
}
@@ -7884,8 +7888,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {

.cpuid_update = vmx_cpuid_update,

- .rdtscp_supported = vmx_rdtscp_supported,
-
.set_supported_cpuid = vmx_set_supported_cpuid,

.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
--
2.24.1