KVM: VMX: Cache MSR_IA32_VMX_MISC in vmcs_config

Like other host VMX control MSRs, MSR_IA32_VMX_MISC can be cached in
vmcs_config to avoid the need to re-read it later, e.g. from
cpu_has_vmx_intel_pt() or cpu_has_vmx_shadow_vmcs().

No (real) functional change intended.

Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220830133737.1539624-33-vkuznets@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index faee1db8b0e091581c704c65b85a28f98769ed53..87c4e46daf3725953f1ecac77dd8a64b9c65704c 100644 (file)
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -65,6 +65,7 @@ struct vmcs_config {
        u64 cpu_based_3rd_exec_ctrl;
        u32 vmexit_ctrl;
        u32 vmentry_ctrl;
+       u64 misc;
        struct nested_vmx_msrs nested;
 };
 extern struct vmcs_config vmcs_config;
@@ -225,11 +226,8 @@ static inline bool cpu_has_vmx_vmfunc(void)
 
 static inline bool cpu_has_vmx_shadow_vmcs(void)
 {
-       u64 vmx_msr;
-
        /* check if the cpu supports writing r/o exit information fields */
-       rdmsrl(MSR_IA32_VMX_MISC, vmx_msr);
-       if (!(vmx_msr & MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS))
+       if (!(vmcs_config.misc & MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS))
                return false;
 
        return vmcs_config.cpu_based_2nd_exec_ctrl &
@@ -371,10 +369,7 @@ static inline bool cpu_has_vmx_invvpid_global(void)
 
 static inline bool cpu_has_vmx_intel_pt(void)
 {
-       u64 vmx_msr;
-
-       rdmsrl(MSR_IA32_VMX_MISC, vmx_msr);
-       return (vmx_msr & MSR_IA32_VMX_MISC_INTEL_PT) &&
+       return (vmcs_config.misc & MSR_IA32_VMX_MISC_INTEL_PT) &&
                (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA) &&
                (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL);
 }

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e12e6e11eae0fa4870ba0ccff333ee4053befefa..e624f4c53021b9a3be526abdd5c84babe5d3b866 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2555,6 +2555,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
        u64 _cpu_based_3rd_exec_control = 0;
        u32 _vmexit_control = 0;
        u32 _vmentry_control = 0;
+       u64 misc_msr;
        int i;
 
        /*
@@ -2688,6 +2689,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
        if (((vmx_msr_high >> 18) & 15) != 6)
                return -EIO;
 
+       rdmsrl(MSR_IA32_VMX_MISC, misc_msr);
+
        vmcs_conf->size = vmx_msr_high & 0x1fff;
        vmcs_conf->basic_cap = vmx_msr_high & ~0x1fff;
 
@@ -2699,6 +2702,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
        vmcs_conf->cpu_based_3rd_exec_ctrl = _cpu_based_3rd_exec_control;
        vmcs_conf->vmexit_ctrl         = _vmexit_control;
        vmcs_conf->vmentry_ctrl        = _vmentry_control;
+       vmcs_conf->misc = misc_msr;
 
        return 0;
 }
@@ -8315,11 +8319,9 @@ static __init int hardware_setup(void)
 
        if (enable_preemption_timer) {
                u64 use_timer_freq = 5000ULL * 1000 * 1000;
-               u64 vmx_msr;
 
-               rdmsrl(MSR_IA32_VMX_MISC, vmx_msr);
                cpu_preemption_timer_multi =
-                       vmx_msr & VMX_MISC_PREEMPTION_TIMER_RATE_MASK;
+                       vmcs_config.misc & VMX_MISC_PREEMPTION_TIMER_RATE_MASK;
 
                if (tsc_khz)
                        use_timer_freq = (u64)tsc_khz * 1000;