linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>, kvm@vger.kernel.org
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Junaid Shahid <junaids@google.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 7/9] KVM: nSVM: implement nested_svm_load_cr3() and use it for host->guest switch
Date: Fri, 10 Jul 2020 14:08:30 +0200	[thread overview]
Message-ID: <353dc97c-9754-68f9-6fb7-13671995e0a2@redhat.com> (raw)
In-Reply-To: <87blknvbre.fsf@vitty.brq.redhat.com>

On 10/07/20 13:40, Vitaly Kuznetsov wrote:
> Hm, it seems I missed svm_set_nested_state() path
> completely. Surprisingly, state_test didn't fail)
> 
> I'm struggling a bit to understand why we don't have kvm_set_cr3() on
> svm_set_nested_state() path: enter_svm_guest_mode() does it through
> nested_prepare_vmcb_save() but it is skipped in svm_set_nested_state().
> Don't we need it at least for !npt_enabled case?

In svm_set_nested_state you'll have CR3 already set to the right value.
 On the source, KVM_GET_SREGS returns the vmcb12's CR3 and it is already
restored with KVM_SET_SREGS on the destination before set_nested_state.

So, only the nested_cr3 has to be set.

Paolo

> We'll have to extract
> nested_cr3 from nested_vmcb then.


  reply	other threads:[~2020-07-10 12:08 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09 14:53 [PATCH v3 0/9] KVM: nSVM: fixes for CR3/MMU switch upon nested guest entry/exit Vitaly Kuznetsov
2020-07-09 14:53 ` [PATCH v3 1/9] KVM: nSVM: split kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu() Vitaly Kuznetsov
2020-07-09 14:53 ` [PATCH v3 2/9] KVM: nSVM: stop dereferencing vcpu->arch.mmu to get the context in kvm_init_shadow{,_npt}_mmu() Vitaly Kuznetsov
2020-07-09 17:47   ` Paolo Bonzini
2020-07-09 14:53 ` [PATCH v3 3/9] KVM: nSVM: reset nested_run_pending upon nested_svm_vmrun_msrpm() failure Vitaly Kuznetsov
2020-07-09 17:48   ` Paolo Bonzini
2020-07-09 14:53 ` [PATCH v3 4/9] KVM: nSVM: prepare to handle errors from enter_svm_guest_mode() Vitaly Kuznetsov
2020-07-09 14:53 ` [PATCH v3 5/9] KVM: nSVM: introduce nested_svm_load_cr3() Vitaly Kuznetsov
2020-07-09 14:53 ` [PATCH v3 6/9] KVM: nSVM: move kvm_set_cr3() after nested_svm_uninit_mmu_context() Vitaly Kuznetsov
2020-07-09 17:51   ` Paolo Bonzini
2020-07-09 14:53 ` [PATCH v3 7/9] KVM: nSVM: implement nested_svm_load_cr3() and use it for host->guest switch Vitaly Kuznetsov
2020-07-09 17:57   ` Paolo Bonzini
2020-07-09 17:59     ` Paolo Bonzini
2020-07-10 11:40       ` Vitaly Kuznetsov
2020-07-10 12:08         ` Paolo Bonzini [this message]
2020-07-10 12:30           ` Vitaly Kuznetsov
2020-07-09 14:53 ` [PATCH v3 8/9] KVM: nSVM: use nested_svm_load_cr3() on guest->host switch Vitaly Kuznetsov
2020-07-09 14:53 ` [PATCH v3 9/9] KVM: x86: drop superfluous mmu_check_root() from fast_pgd_switch() Vitaly Kuznetsov
2020-07-09 18:01 ` [PATCH v3 0/9] KVM: nSVM: fixes for CR3/MMU switch upon nested guest entry/exit Paolo Bonzini

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=353dc97c-9754-68f9-6fb7-13671995e0a2@redhat.com \
    --to=pbonzini@redhat.com \
    --cc=jmattson@google.com \
    --cc=junaids@google.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sean.j.christopherson@intel.com \
    --cc=vkuznets@redhat.com \
    --cc=wanpengli@tencent.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).