From: Tom Lendacky <thomas.lendacky@amd.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>,
the arch/x86 maintainers <x86@kernel.org>,
Kexec Mailing List <kexec@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Dave Young <dyoung@redhat.com>, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v1 1/2] x86/mm, kexec: Fix memory corruption with SME on successive kexecs
Date: Thu, 27 Jul 2017 13:47:42 -0500 [thread overview]
Message-ID: <a052ad5b-cb70-7279-6837-0cc6e7f8a19c@amd.com> (raw)
In-Reply-To: <CA+55aFwRykCYz0p1WTJeehcpXwqN10UGOJrMcTRB4zUxt=D5ng@mail.gmail.com>
On 7/27/2017 12:34 PM, Linus Torvalds wrote:
> On Thu, Jul 27, 2017 at 7:15 AM, Tom Lendacky <thomas.lendacky@amd.com> wrote:
>>
>> I can #ifdef the wbinvd based on whether AMD_MEM_ENCRYPT is configured
>> or not so that the wbinvd is avoided if not configured.
>
> I suspect an ifdef will be useless, since things like distro kernels
> tend to enable everything.
>
> So it should probably be disabled dynamically, and only done if the
> AMD memory encryption thing has actually been active.
>
> [ There have also been various actual errata with wbinvd, so there
> tends to be a non-performance reason to try to avoid it unless
> strictly required ]
Ok, I'll make the wbinvd a run time decision based on whether SME is
active at the time.
Thanks,
Tom
>
> Linus
>
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prev parent reply other threads:[~2017-07-27 18:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-26 18:04 [PATCH v1 0/2] x86: Secure Memory Encryption (SME) fixes 2017-07-26 Tom Lendacky
2017-07-26 18:04 ` [PATCH v1 1/2] x86/mm, kexec: Fix memory corruption with SME on successive kexecs Tom Lendacky
2017-07-27 7:17 ` Ingo Molnar
2017-07-27 14:15 ` Tom Lendacky
2017-07-27 17:34 ` Linus Torvalds
2017-07-27 18:47 ` Tom Lendacky [this message]
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