From: Kai Huang <kai.huang@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Michael Roth <michael.roth@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH 2/4] KVM: x86/mmu: Fully re-evaluate MMIO caching when SPTE masks change
Date: Tue, 02 Aug 2022 08:46:26 +1200 [thread overview]
Message-ID: <244f619a4e7a1c7079830d12379872a111da418d.camel@intel.com> (raw)
In-Reply-To: <YufgCR9CpeoVWKF7@google.com>
On Mon, 2022-08-01 at 14:15 +0000, Sean Christopherson wrote:
> On Mon, Aug 01, 2022, Kai Huang wrote:
> > On Fri, 2022-07-29 at 15:07 +0000, Sean Christopherson wrote:
> > > Lastly, in prepration for TDX, enable_mmio_caching should be changed to key off
> > > of the _mask_, not the value. E.g. for TDX, the value will be '0', but the mask
> > > should be SUPPRESS_VE | RWX.
> >
> > Agreed. But perhaps in another patch. We need to re-define what does
> > mask/value mean to enable_mmio_caching.
>
> There's no need to redefine what they mean, the only change that needs to be made
> is handle the scenario where desire value is '0'. Maybe that's all you mean by
> "redefine"?
My thinking is only when mask and value both are 0, enable_mmio_caching is
considered disabled. vlaue=0 is valid when enable_mmio_caching is true as you
said.
>
> Another thing to note is that only the value needs to be per-VM, the mask can be
> KVM-wide, i.e. "mask = SUPPRESS_VE | RWX" will work for TDX and non-TDX VMs when
> EPT is enabled.
Yeah, but is more like VMX and TDX both *happen* to have the same mask?
Theoretically, VMX only need RWX to trigger EPT misconfiguration but doesn't
need SUPPRESS_VE.
I don't see making mask/value both per-vm is a big issue?
--
Thanks,
-Kai
next prev parent reply other threads:[~2022-08-01 20:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-28 22:17 [PATCH 0/4] KVM: x86/mmu: MMIO caching bug fixes Sean Christopherson
2022-07-28 22:17 ` [PATCH 1/4] KVM: x86: Tag kvm_mmu_x86_module_init() with __init Sean Christopherson
2022-07-29 2:14 ` Kai Huang
2022-07-28 22:17 ` [PATCH 2/4] KVM: x86/mmu: Fully re-evaluate MMIO caching when SPTE masks change Sean Christopherson
2022-07-29 2:39 ` Kai Huang
2022-07-29 15:07 ` Sean Christopherson
2022-08-01 9:24 ` Kai Huang
2022-08-01 14:15 ` Sean Christopherson
2022-08-01 20:46 ` Kai Huang [this message]
2022-08-01 23:20 ` Sean Christopherson
2022-08-02 0:05 ` Kai Huang
2022-08-02 21:15 ` Sean Christopherson
2022-08-02 22:19 ` Kai Huang
2022-08-02 23:05 ` Sean Christopherson
2022-08-02 23:42 ` Kai Huang
2022-07-28 22:17 ` [PATCH 3/4] KVM: SVM: Adjust MMIO masks (for caching) before doing SEV(-ES) setup Sean Christopherson
2022-07-29 2:06 ` Kai Huang
2022-07-29 18:15 ` Sean Christopherson
2022-07-28 22:17 ` [PATCH 4/4] KVM: SVM: Disable SEV-ES support if MMIO caching is disable Sean Christopherson
2022-07-29 2:12 ` Kai Huang
2022-07-29 15:21 ` Sean Christopherson
2022-08-01 9:30 ` Kai Huang
2022-07-29 1:09 ` [PATCH 0/4] KVM: x86/mmu: MMIO caching bug fixes Michael Roth
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=244f619a4e7a1c7079830d12379872a111da418d.camel@intel.com \
--to=kai.huang@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=michael.roth@amd.com \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=thomas.lendacky@amd.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).