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Subject[PATCH] kvm: x86: refine kvm_get_arch_capabilities()
Date
1. Using X86_FEATURE_ARCH_CAPABILITIES to enumerate the existence of
MSR_IA32_ARCH_CAPABILITIES to avoid using rdmsrl_safe().

2. Since kvm_get_arch_capabilities() is only used in this file, making
it static.

Signed-off-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
---
arch/x86/include/asm/kvm_host.h | 1 -
arch/x86/kvm/x86.c | 8 ++++----
2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a9d03af34030..d4ae67870764 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1526,7 +1526,6 @@ int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low,
unsigned long ipi_bitmap_high, u32 min,
unsigned long icr, int op_64_bit);

-u64 kvm_get_arch_capabilities(void);
void kvm_define_shared_msr(unsigned index, u32 msr);
int kvm_set_shared_msr(unsigned index, u64 val, u64 mask);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a0d1fc80ac5a..ba8e269a8cd2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1205,11 +1205,12 @@ static u32 msr_based_features[] = {

static unsigned int num_msr_based_features;

-u64 kvm_get_arch_capabilities(void)
+static u64 kvm_get_arch_capabilities(void)
{
- u64 data;
+ u64 data = 0;

- rdmsrl_safe(MSR_IA32_ARCH_CAPABILITIES, &data);
+ if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
+ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, data);

/*
* If we're doing cache flushes (either "always" or "cond")
@@ -1225,7 +1226,6 @@ u64 kvm_get_arch_capabilities(void)

return data;
}
-EXPORT_SYMBOL_GPL(kvm_get_arch_capabilities);

static int kvm_get_msr_feature(struct kvm_msr_entry *msr)
{
--
2.19.1
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