From: Sean Christopherson <seanjc@google.com>
To: Sasha Levin <sashal@kernel.org>
Cc: linux-kernel@vger.kernel.org, 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>,
Thomas Gleixner <tglx@kernel.org>,
x86@kernel.org
Subject: Re: [PATCH v2 10/20] x86/sev: Use non-instrumented bitops in the GHCB accessors
Date: Wed, 4 Nov 2026 05:36:29 -0800 [thread overview]
Message-ID: <aus03eVALC1m86Aa@google.com> (raw)
In-Reply-To: <20261103015238.3780910-11-sashal@kernel.org>
On Mon, Nov 02, 2026, Sasha Levin wrote:
> 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>
> ---
Reviewed-by: Sean Christopherson <seanjc@google.com>
next prev parent reply other threads:[~2026-11-04 13:36 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-03 1:52 [PATCH v2 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Sasha Levin
2026-11-03 1:52 ` [PATCH v2 01/20] coverage: move gcov and kcov under kernel/coverage/ Sasha Levin
2026-11-03 1:52 ` [PATCH v2 02/20] kbuild: unify static coverage instrumentation as COVERAGE_PROFILE Sasha Levin
2026-11-03 1:52 ` [PATCH v2 03/20] coverage: add a common debugfs interface Sasha Levin
2026-11-03 1:52 ` [PATCH v2 04/20] compiler_types.h: Don't instrument __always_inline functions for coverage Sasha Levin
2026-11-03 1:52 ` [PATCH v2 05/20] context_tracking: Always inline the empty stubs called from noinstr code Sasha Levin
2026-11-03 1:52 ` [PATCH v2 06/20] lockdep: " Sasha Levin
2026-11-03 1:52 ` [PATCH v2 07/20] perf: Always inline the empty perf_lopwr_cb() stub Sasha Levin
2026-11-03 1:52 ` [PATCH v2 08/20] rseq: Always inline the empty stubs called from noinstr code Sasha Levin
2026-11-03 1:52 ` [PATCH v2 09/20] x86: Always inline " Sasha Levin
2026-11-03 1:52 ` [PATCH v2 10/20] x86/sev: Use non-instrumented bitops in the GHCB accessors Sasha Levin
2026-11-04 13:36 ` Sean Christopherson [this message]
2026-11-03 1:52 ` [PATCH v2 11/20] objtool: Detect code coverage instrumentation in noinstr code Sasha Levin
2026-11-03 1:52 ` [PATCH v2 12/20] x86/sev: Stop excluding noinstr.o from code coverage Sasha Levin
2026-11-03 1:52 ` [PATCH v2 13/20] x86/entry: Stop excluding the entry code from KCOV Sasha Levin
2026-11-03 1:52 ` [PATCH v2 14/20] coverage: add Clang's source-based code coverage Sasha Levin
2026-11-03 1:52 ` [PATCH v2 15/20] x86: Enable " Sasha Levin
2026-11-03 1:52 ` [PATCH v2 16/20] coverage: add MC/DC measurement Sasha Levin
2026-11-03 1:52 ` [PATCH v2 17/20] gcov: fix gcov_info_add() merge semantics for IOR counters Sasha Levin
2026-11-03 1:52 ` [PATCH v2 18/20] kconfig: add CC_HAS_CONDITION_COVERAGE for MC/DC support detection Sasha Levin
2026-11-03 1:52 ` [PATCH v2 19/20] gcov: add MC/DC condition coverage support Sasha Levin
2026-11-03 1:52 ` [PATCH v2 20/20] Documentation: dev-tools: document the common code coverage interface Sasha Levin
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