From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Peter Shier <pshier@google.com>, Oliver Upton <oupton@google.com>
Subject: Re: [PATCH] KVM: x86: Reset MMU context if guest toggles CR4.SMAP or CR4.PKE
Date: Fri, 25 Sep 2020 14:56:47 +0200 [thread overview]
Message-ID: <52f35035-94cd-9a4e-263a-6b3641e5d44c@redhat.com> (raw)
In-Reply-To: <20200923215352.17756-1-sean.j.christopherson@intel.com>
On 23/09/20 23:53, Sean Christopherson wrote:
> Reset the MMU context during kvm_set_cr4() if SMAP or PKE is toggled.
> Recent commits to (correctly) not reload PDPTRs when SMAP/PKE are
> toggled inadvertantly skipped the MMU context reset due to the mask
> of bits that triggers PDPTR loads also being used to trigger MMU context
> resets.
>
> Fixes: 427890aff855 ("kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode")
> Fixes: cb957adb4ea4 ("kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode")
> Cc: Jim Mattson <jmattson@google.com>
> Cc: Peter Shier <pshier@google.com>
> Cc: Oliver Upton <oupton@google.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
> arch/x86/kvm/x86.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 17f4995e80a7..fd0da41bc149 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -977,6 +977,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
> unsigned long old_cr4 = kvm_read_cr4(vcpu);
> unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |
> X86_CR4_SMEP;
> + unsigned long mmu_role_bits = pdptr_bits | X86_CR4_SMAP | X86_CR4_PKE;
>
> if (kvm_valid_cr4(vcpu, cr4))
> return 1;
> @@ -1004,7 +1005,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
> if (kvm_x86_ops.set_cr4(vcpu, cr4))
> return 1;
>
> - if (((cr4 ^ old_cr4) & pdptr_bits) ||
> + if (((cr4 ^ old_cr4) & mmu_role_bits) ||
> (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
> kvm_mmu_reset_context(vcpu);
>
>
Queued, thanks.
Paolo
prev parent reply other threads:[~2020-09-25 12:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 21:53 [PATCH] KVM: x86: Reset MMU context if guest toggles CR4.SMAP or CR4.PKE Sean Christopherson
2020-09-24 21:48 ` Jim Mattson
2020-09-25 12:56 ` Paolo Bonzini [this message]
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=52f35035-94cd-9a4e-263a-6b3641e5d44c@redhat.com \
--to=pbonzini@redhat.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oupton@google.com \
--cc=pshier@google.com \
--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).