From: Sasha Levin <sashal@kernel.org>
To: Sean Christopherson <seanjc@google.com>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Borislav Petkov <bp@alien8.de>,
tglx@linutronix.de, peterz@infradead.org, jpoimboe@kernel.org,
corbet@lwn.net, mingo@redhat.com, dave.hansen@linux.intel.com,
x86@kernel.org, pbonzini@redhat.com, thomas.lendacky@amd.com,
mario.limonciello@amd.com, perry.yuan@amd.com,
kai.huang@intel.com, xiaoyao.li@intel.com, tony.luck@intel.com,
xin3.li@intel.com, kan.liang@linux.intel.com,
linux-doc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 6.14 317/642] x86/bugs: KVM: Add support for SRSO_MSR_FIX
Date: Tue, 20 May 2025 10:13:04 -0400 [thread overview]
Message-ID: <aCyN8IoJXk5G3eR6@lappy> (raw)
In-Reply-To: <aBk9nVsmHObvxU7o@google.com>
On Mon, May 05, 2025 at 03:37:17PM -0700, Sean Christopherson wrote:
>On Mon, May 05, 2025, Sasha Levin wrote:
>> From: Borislav Petkov <bp@alien8.de>
>>
>> [ Upstream commit 8442df2b49ed9bcd67833ad4f091d15ac91efd00 ]
>>
>> Add support for
>>
>> CPUID Fn8000_0021_EAX[31] (SRSO_MSR_FIX). If this bit is 1, it
>> indicates that software may use MSR BP_CFG[BpSpecReduce] to mitigate
>> SRSO.
>>
>> Enable BpSpecReduce to mitigate SRSO across guest/host boundaries.
>>
>> Switch back to enabling the bit when virtualization is enabled and to
>> clear the bit when virtualization is disabled because using a MSR slot
>> would clear the bit when the guest is exited and any training the guest
>> has done, would potentially influence the host kernel when execution
>> enters the kernel and hasn't VMRUN the guest yet.
>>
>> More detail on the public thread in Link below.
>>
>> Co-developed-by: Sean Christopherson <seanjc@google.com>
>> Signed-off-by: Sean Christopherson <seanjc@google.com>
>> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
>> Link: https://lore.kernel.org/r/20241202120416.6054-1-bp@kernel.org
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>
>Can we please hold off on this until the fix lands[1]? This version introduces
>a very measurable performance regression[2] for non-KVM use cases.
Sure, I'll drop it. Thanks!
--
Thanks,
Sasha
next prev parent reply other threads:[~2025-05-20 14:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20250505221419.2672473-1-sashal@kernel.org>
2025-05-05 22:04 ` [PATCH AUTOSEL 6.14 083/642] x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers Sasha Levin
2025-05-05 22:05 ` [PATCH AUTOSEL 6.14 124/642] vfio/pci: Handle INTx IRQ_NOTCONNECTED Sasha Levin
2025-05-05 22:08 ` [PATCH AUTOSEL 6.14 317/642] x86/bugs: KVM: Add support for SRSO_MSR_FIX Sasha Levin
2025-05-05 22:37 ` Sean Christopherson
2025-05-20 14:13 ` Sasha Levin [this message]
2025-05-05 22:09 ` [PATCH AUTOSEL 6.14 330/642] vhost-scsi: Return queue full for page alloc failures during copy Sasha Levin
2025-05-05 22:48 ` Mike Christie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aCyN8IoJXk5G3eR6@lappy \
--to=sashal@kernel.org \
--cc=bp@alien8.de \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=jpoimboe@kernel.org \
--cc=kai.huang@intel.com \
--cc=kan.liang@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mario.limonciello@amd.com \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=perry.yuan@amd.com \
--cc=peterz@infradead.org \
--cc=seanjc@google.com \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
--cc=xiaoyao.li@intel.com \
--cc=xin3.li@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).