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Subject[PATCH v2 3/3] x86/cpu, KVM: Use helper function to read MSR_IA32_ARCH_CAPABILITIES
Date
KVM open-codes x86_read_arch_cap_msr() in a few places. Eliminate them
by exposing the helper function and using it directly.

No functional change intended.

Signed-off-by: Chao Gao <chao.gao@intel.com>
---
arch/x86/kernel/cpu/common.c | 1 +
arch/x86/kvm/vmx/vmx.c | 19 +++++--------------
arch/x86/kvm/x86.c | 7 +------
3 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 80710a68ef7d..b34dd3f3e6c4 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1315,6 +1315,7 @@ u64 x86_read_arch_cap_msr(void)

return ia32_cap;
}
+EXPORT_SYMBOL_GPL(x86_read_arch_cap_msr);

static bool arch_cap_mmio_immune(u64 ia32_cap)
{
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 8274ef5e89e5..3dec4a4f637e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -255,14 +255,9 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf)
return 0;
}

- if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) {
- u64 msr;
-
- rdmsrl(MSR_IA32_ARCH_CAPABILITIES, msr);
- if (msr & ARCH_CAP_SKIP_VMENTRY_L1DFLUSH) {
- l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED;
- return 0;
- }
+ if (x86_read_arch_cap_msr() & ARCH_CAP_SKIP_VMENTRY_L1DFLUSH) {
+ l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED;
+ return 0;
}

/* If set to auto use the default l1tf mitigation method */
@@ -394,13 +389,9 @@ static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)

static void vmx_setup_fb_clear_ctrl(void)
{
- u64 msr;
-
- if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES) &&
- !boot_cpu_has_bug(X86_BUG_MDS) &&
+ if (!boot_cpu_has_bug(X86_BUG_MDS) &&
!boot_cpu_has_bug(X86_BUG_TAA)) {
- rdmsrl(MSR_IA32_ARCH_CAPABILITIES, msr);
- if (msr & ARCH_CAP_FB_CLEAR_CTRL)
+ if (x86_read_arch_cap_msr() & ARCH_CAP_FB_CLEAR_CTRL)
vmx_fb_clear_ctrl_available = true;
}
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f7838260c183..b1bdb84ac10f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1612,12 +1612,7 @@ static bool kvm_is_immutable_feature_msr(u32 msr)

static u64 kvm_get_arch_capabilities(void)
{
- u64 data = 0;
-
- if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) {
- rdmsrl(MSR_IA32_ARCH_CAPABILITIES, data);
- data &= KVM_SUPPORTED_ARCH_CAP;
- }
+ u64 data = x86_read_arch_cap_msr() & KVM_SUPPORTED_ARCH_CAP;

/*
* If nx_huge_pages is enabled, KVM's shadow paging will ensure that
--
2.40.0
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