From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>, Chuck Wolber <chuck@wolber.net>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
kvm@vger.kernel.org, Marco Elver <elver@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Sean Christopherson <seanjc@google.com>,
Thomas Gleixner <tglx@kernel.org>,
x86@kernel.org
Subject: [RFC PATCH 10/20] x86/sev: Use non-instrumented bitops in the GHCB accessors
Date: Wed, 28 Oct 2026 07:59:34 -0400 [thread overview]
Message-ID: <20261028120034.871983-11-sashal@kernel.org> (raw)
In-Reply-To: <20261028120034.871983-1-sashal@kernel.org>
The GHCB accessors are used from noinstr code, such as
__sev_es_nmi_complete(), but use test_bit() and __set_bit(), which
call the KASAN and KCSAN checks. arch/x86/coco/sev/Makefile disables
KASAN and KCSAN for noinstr.o, which turns those checks into empty
stubs, but they still have to be inlined. Instrumentation such as gcov
can prevent that and leave calls to kasan_check_write() behind in
noinstr code.
Use the arch_ bitops, which aren't instrumented, as is done elsewhere
for noinstr code.
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/include/asm/svm.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 83fd49b26a4b1..9881c702a8f01 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -674,8 +674,8 @@ static inline void __unused_size_checks(void)
#define DEFINE_GHCB_ACCESSORS(field) \
static __always_inline bool ghcb_##field##_is_valid(const struct ghcb *ghcb) \
{ \
- return test_bit(GHCB_BITMAP_IDX(field), \
- (unsigned long *)&ghcb->save.valid_bitmap); \
+ return arch_test_bit(GHCB_BITMAP_IDX(field), \
+ (unsigned long *)&ghcb->save.valid_bitmap); \
} \
\
static __always_inline u64 ghcb_get_##field(struct ghcb *ghcb) \
@@ -690,8 +690,8 @@ static inline void __unused_size_checks(void)
\
static __always_inline void ghcb_set_##field(struct ghcb *ghcb, u64 value) \
{ \
- __set_bit(GHCB_BITMAP_IDX(field), \
- (unsigned long *)&ghcb->save.valid_bitmap); \
+ arch___set_bit(GHCB_BITMAP_IDX(field), \
+ (unsigned long *)&ghcb->save.valid_bitmap); \
ghcb->save.field = value; \
}
--
2.53.0
parent reply other threads:[~2026-10-28 12:01 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20261028120034.871983-1-sashal@kernel.org>]
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