From: Yang Weijiang <weijiang.yang@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: rkrcmar@redhat.com, sean.j.christopherson@intel.com,
jmattson@google.com, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, mst@redhat.com, yu-cheng.yu@intel.com,
yi.z.zhang@intel.com, hjl.tools@gmail.com,
Zhang Yi Z <yi.z.zhang@linux.intel.com>
Subject: Re: [PATCH v2 1/7] KVM:VMX: Define CET VMCS fields and bits
Date: Tue, 29 Jan 2019 16:29:17 +0800 [thread overview]
Message-ID: <20190129082917.GA32725@local-michael-cet-test.sh.intel.com> (raw)
In-Reply-To: <4d9a5393-163b-f32a-4657-cec54093ee88@redhat.com>
On Tue, Jan 29, 2019 at 04:19:34PM +0100, Paolo Bonzini wrote:
> On 28/01/19 11:33, Yang Weijiang wrote:
> >> There is no code in this series to pass these fields to and from
> >> userspace, and also to save/restore U_CET, INT_SSP_TAB, PL0_SSP and
> >> PL3_SSP across context switches.
> >>
> > The kernel consumes these MSRs, please see kernel CET patch:
> > https://lkml.org/lkml/fancy/2018/11/20/225
>
> Still, even if the kernel saves these fields across context switch in
> XSAVE areas, KVM must support accesses to the MSRs from userspace, for
> example in order to perform live migration.
>
> For example, when reading/writing these in kvm_set_msr or
> kvm_get_msr_common, you would have to do a read/write from the host
> MSRs. You also have to put kvm_load_guest_fpu/kvm_put_guest_fpu calls
> in __msr_io.
Thanks, you're right, if we want to support live migration we need do that.
However, this feature relies on quite a few external
dependencies, e.g., cpu capabilities, kernel version and configuration, we
don't support live migration right now. what's your opinion?
>
> Thanks,
>
> Paolo
>
> >> In addition, PL1_SSP and PL2_SSP should be supported even if the guest
> >> doesn't use them. It makes sense to avoid intercepting them, but they
> >> should still be supported and switched (possibly only if nonzero).
> >>
> >> Am I missing something, for example a dependency on host CET support?
> >> If not, how was this series tested?
> >>
> > The guest CET feature is tested with kernel CET patches on internal
> > virtual platform.
> >
next prev parent reply other threads:[~2019-01-30 1:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-22 20:59 [PATCH v2 0/7] This patch-set is to enable Guest CET support Yang Weijiang
2019-01-22 20:59 ` [PATCH v2 1/7] KVM:VMX: Define CET VMCS fields and bits Yang Weijiang
2019-01-25 18:02 ` Paolo Bonzini
2019-01-28 10:33 ` Yang Weijiang
2019-01-29 15:19 ` Paolo Bonzini
2019-01-29 8:29 ` Yang Weijiang [this message]
2019-01-30 8:32 ` Paolo Bonzini
2019-03-04 18:56 ` Sean Christopherson
2019-03-08 9:15 ` Paolo Bonzini
2019-03-08 15:50 ` Sean Christopherson
2019-03-08 16:34 ` Paolo Bonzini
2019-01-25 22:30 ` Sean Christopherson
2019-01-29 17:47 ` Jim Mattson
2019-01-29 18:01 ` Jim Mattson
[not found] ` <20190129182750.GB8156@linux.intel.com>
2019-01-29 8:34 ` Yang Weijiang
2019-01-22 20:59 ` [PATCH v2 2/7] KVM:CPUID: Define CET CPUID bits and CR4.CET master enable bit Yang Weijiang
2019-01-22 20:59 ` [PATCH v2 3/7] KVM:CPUID: Add CPUID support for CET xsaves component query Yang Weijiang
2019-01-25 17:57 ` Paolo Bonzini
2019-01-25 22:40 ` Sean Christopherson
2019-01-22 20:59 ` [PATCH v2 4/7] KVM:CPUID: Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1) Yang Weijiang
2019-01-25 22:47 ` Sean Christopherson
2019-01-22 20:59 ` [PATCH v2 5/7] KVM:VMX: Pass through host CET related MSRs to Guest Yang Weijiang
2019-01-25 22:50 ` Sean Christopherson
2019-01-22 20:59 ` [PATCH v2 6/7] KVM:VMX: Load Guest CET via VMCS when CET is enabled in Guest Yang Weijiang
2019-01-25 22:56 ` Sean Christopherson
2019-01-30 15:16 ` Yang Weijiang
2019-01-22 20:59 ` [PATCH v2 7/7] KVM:X86: Enable MSR_IA32_XSS bit 11 and 12 for CET xsaves/xrstors Yang Weijiang
2019-01-25 23:03 ` Sean Christopherson
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=20190129082917.GA32725@local-michael-cet-test.sh.intel.com \
--to=weijiang.yang@intel.com \
--cc=hjl.tools@gmail.com \
--cc=jmattson@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=sean.j.christopherson@intel.com \
--cc=yi.z.zhang@intel.com \
--cc=yi.z.zhang@linux.intel.com \
--cc=yu-cheng.yu@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
all inboxes | Powered by JetHome®