From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Wei Huang <wei.huang2@amd.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
vkuznets@redhat.com, joro@8bytes.org, bp@alien8.de,
tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
jmattson@google.com, wanpengli@tencent.com, bsd@redhat.com,
dgilbert@redhat.com, mlevitsk@redhat.com
Subject: Re: [PATCH 1/2] KVM: x86: Add emulation support for #GP triggered by VM instructions
Date: Wed, 13 Jan 2021 13:35:02 +0100 [thread overview]
Message-ID: <51f96502-95d2-569c-2973-eb839f84019f@redhat.com> (raw)
In-Reply-To: <X/3fbaO1ZarMdjft@google.com>
On 12/01/21 18:42, Sean Christopherson wrote:
> On a related topic, it feels like nested should be disabled by default on SVM
> until it's truly ready for primetime, with the patch tagged for stable. That
> way we don't have to worry about crafting non-trivial fixes (like this one) to
> make them backport-friendly.
Well, that's historical; I wish it had been disabled by default back in
the day.
However, after 10 years and after the shakedown last year, it's hard to
justify breaking backwards compatibility. Nested SVM is not any less
ready than nested VMX---just a little less optimized for things such as
TLB flushes and ASID/VPID---even without this fix. The erratum has
visible effects only on a minority of AMD systems (it depends on an
unlucky placement of TSEG on L0), and it is easy to work around it by
lowering the amount of <4G memory in L1.
Paolo
next prev parent reply other threads:[~2021-01-13 12:36 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 6:37 [PATCH 1/2] KVM: x86: Add emulation support for #GP triggered by VM instructions Wei Huang
2021-01-12 6:37 ` [PATCH 2/2] KVM: SVM: Add support for VMCB address check change Wei Huang
2021-01-12 19:18 ` Sean Christopherson
2021-01-14 11:39 ` Maxim Levitsky
2021-01-14 12:04 ` Maxim Levitsky
2021-01-12 11:09 ` [PATCH 1/2] KVM: x86: Add emulation support for #GP triggered by VM instructions Maxim Levitsky
2021-01-12 21:05 ` Wei Huang
2021-01-12 12:15 ` Vitaly Kuznetsov
2021-01-12 15:11 ` Andy Lutomirski
2021-01-12 15:17 ` Maxim Levitsky
2021-01-12 15:22 ` Andy Lutomirski
2021-01-12 15:46 ` Bandan Das
2021-01-12 15:51 ` Andy Lutomirski
2021-01-12 17:56 ` Sean Christopherson
2021-01-13 4:55 ` Wei Huang
2021-01-12 21:50 ` Wei Huang
2021-01-12 14:01 ` Paolo Bonzini
2021-01-12 17:42 ` Sean Christopherson
2021-01-13 12:35 ` Paolo Bonzini [this message]
2021-01-15 7:00 ` Wei Huang
2021-01-17 18:20 ` Paolo Bonzini
2021-01-12 17:36 ` Sean Christopherson
2021-01-12 17:59 ` Sean Christopherson
2021-01-12 18:58 ` Andy Lutomirski
2021-01-13 5:15 ` Wei Huang
2021-01-14 11:42 ` Maxim Levitsky
2021-01-13 5:03 ` Wei Huang
2021-01-13 12:40 ` Paolo Bonzini
2021-01-12 19:40 ` Sean Christopherson
2021-01-12 20:00 ` Bandan Das
2021-01-14 11:47 ` Maxim Levitsky
2021-01-14 17:19 ` Sean Christopherson
2021-01-14 11:55 ` Maxim Levitsky
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=51f96502-95d2-569c-2973-eb839f84019f@redhat.com \
--to=pbonzini@redhat.com \
--cc=bp@alien8.de \
--cc=bsd@redhat.com \
--cc=dgilbert@redhat.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=mlevitsk@redhat.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=wei.huang2@amd.com \
--cc=x86@kernel.org \
/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).