[kvm-unit-tests PATCH 05/16] x86: Implement get_supported_xcr0() using X86_PROPERTY_SUPPORTED_XCR0_{LO,HI}

Sean Christopherson seanjc at google.com
Thu May 29 15:19:18 PDT 2025


Use X86_PROPERTY_SUPPORTED_XCR0_{LO,HI} to implement get_supported_xcr0().

Opportunistically rename the helper and move it to processor.h.

Signed-off-by: Sean Christopherson <seanjc at google.com>
---
 lib/x86/processor.h |  9 +++++++++
 x86/xsave.c         | 11 +----------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 8c6f28a3..cbfd2ee1 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -442,6 +442,15 @@ static inline u8 cpuid_maxphyaddr(void)
 	return this_cpu_property(X86_PROPERTY_MAX_PHY_ADDR);
 }
 
+static inline u64 this_cpu_supported_xcr0(void)
+{
+	if (!this_cpu_has_p(X86_PROPERTY_SUPPORTED_XCR0_LO))
+		return 0;
+
+	return (u64)this_cpu_property(X86_PROPERTY_SUPPORTED_XCR0_LO) |
+	       ((u64)this_cpu_property(X86_PROPERTY_SUPPORTED_XCR0_HI) << 32);
+}
+
 struct far_pointer32 {
 	u32 offset;
 	u16 selector;
diff --git a/x86/xsave.c b/x86/xsave.c
index 5d80f245..cc8e3a0a 100644
--- a/x86/xsave.c
+++ b/x86/xsave.c
@@ -8,15 +8,6 @@
 #define uint64_t unsigned long long
 #endif
 
-static uint64_t get_supported_xcr0(void)
-{
-    struct cpuid r;
-    r = cpuid_indexed(0xd, 0);
-    printf("eax %x, ebx %x, ecx %x, edx %x\n",
-            r.a, r.b, r.c, r.d);
-    return r.a + ((u64)r.d << 32);
-}
-
 #define XCR_XFEATURE_ENABLED_MASK       0x00000000
 #define XCR_XFEATURE_ILLEGAL_MASK       0x00000010
 
@@ -33,7 +24,7 @@ static void test_xsave(void)
 
     printf("Legal instruction testing:\n");
 
-    supported_xcr0 = get_supported_xcr0();
+    supported_xcr0 = this_cpu_supported_xcr0();
     printf("Supported XCR0 bits: %#lx\n", supported_xcr0);
 
     test_bits = XSTATE_FP | XSTATE_SSE;
-- 
2.49.0.1204.g71687c7c1d-goog




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