linux-kernel - [PATCH v3 11/13] KVM: selftests: x86: Remove redundant check that XSAVE is supported

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Message-ID: <20230221163655.920289-12-mizhang@google.com>
Date:   Tue, 21 Feb 2023 16:36:53 +0000
From:   Mingwei Zhang <mizhang@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, linux-kselftest@...r.kernel.org,
        Mingwei Zhang <mizhang@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Venkatesh Srinivas <venkateshs@...gle.com>,
        Aaron Lewis <aaronlewis@...gle.com>,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Chao Gao <chao.gao@...el.com>
Subject: [PATCH v3 11/13] KVM: selftests: x86: Remove redundant check that
 XSAVE is supported

From: Aaron Lewis <aaronlewis@...gle.com>

In amx_test, userspace requires that XSAVE is supported before running
the test, then the guest checks that it is supported after enabling
AMX.  Remove the redundant check in the guest that XSAVE is supported.

Opportunistically, move the check that OSXSAVE is set to immediately
after the guest sets it, rather than in a separate helper.

Signed-off-by: Aaron Lewis <aaronlewis@...gle.com>
Signed-off-by: Mingwei Zhang <mizhang@...gle.com>
---
 tools/testing/selftests/kvm/x86_64/amx_test.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index 1a1565126255..deacd21cf744 100644
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -109,12 +109,6 @@ static inline void __xsavec(struct xstate *xstate, uint64_t rfbm)
 		     : "memory");
 }
 
-static inline void check_cpuid_xsave(void)
-{
-	GUEST_ASSERT(this_cpu_has(X86_FEATURE_XSAVE));
-	GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
-}
-
 static void check_xtile_info(void)
 {
 	GUEST_ASSERT(this_cpu_has_p(X86_PROPERTY_XSTATE_MAX_SIZE_XCR0));
@@ -157,6 +151,7 @@ static void init_regs(void)
 	cr4 = get_cr4();
 	cr4 |= X86_CR4_OSXSAVE;
 	set_cr4(cr4);
+	GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
 
 	xcr0 = __xgetbv(0);
 	xcr0 |= XFEATURE_MASK_XTILE;
@@ -169,7 +164,6 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
 						    struct xstate *xstate)
 {
 	init_regs();
-	check_cpuid_xsave();
 	check_xtile_info();
 	GUEST_SYNC(1);
 
-- 
2.39.2.637.g21b0678d19-goog