From: Tom Lendacky <thomas.lendacky@amd.com>
To: Mario Limonciello <mario.limonciello@amd.com>,
Borislav Petkov <bp@alien8.de>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
hughsient@gmail.com,
Martin Fernandez <martin.fernandez@eclypsium.com>,
linux-kernel@vger.kernel.org,
Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: [PATCH v4] x86/cpu: clear SME feature flag when not in use
Date: Wed, 16 Feb 2022 09:05:07 -0600 [thread overview]
Message-ID: <9fb62811-799a-0df8-2f5e-b6b6990d26e3@amd.com> (raw)
In-Reply-To: <20220216034446.2430634-1-mario.limonciello@amd.com>
On 2/15/22 21:44, Mario Limonciello wrote:
> Currently the SME CPU feature flag is reflective of whether the CPU
> supports the feature but not whether is has been activated by the
> kernel.
>
> Change this around to clear the SME feature flag if the kernel is not
> using it so userspace can determine if it is available and in use
> from `/proc/cpuinfo`.
>
> As the feature flag is cleared on systems where SME isn't active use
> CPUID 0x8000001f to confirm SME availability before calling
> `native_wbinvd`.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
next prev parent reply other threads:[~2022-02-16 15:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-16 3:44 [PATCH v4] x86/cpu: clear SME feature flag when not in use Mario Limonciello
2022-02-16 10:33 ` Borislav Petkov
2022-02-16 13:41 ` Limonciello, Mario
2022-02-16 15:05 ` Tom Lendacky [this message]
2022-02-16 20:16 ` [tip: x86/cpu] x86/cpu: Clear " tip-bot2 for Mario Limonciello
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