From: Junaid Shahid <junaids@google.com>
To: Wanpeng Li <kernellwp@gmail.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Liran Alon" <liran.alon@oracle.com>
Subject: Re: [PATCH v2] KVM: X86: Fix CR3 reserve bits
Date: Sun, 13 May 2018 08:34:05 -0700 [thread overview]
Message-ID: <29625752-1e02-dcd7-7b26-1d5c8c30a8db@google.com> (raw)
In-Reply-To: <1526203487-4967-1-git-send-email-wanpengli@tencent.com>
On 05/13/2018 02:24 AM, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4.
> It should be checked when PCIDE bit is not set, however commit
> 'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on
> its physical address width")' removes the bit 63 checking
> unconditionally. This patch fixes it by checking bit 63 of CR3
> when PCIDE bit is not set in CR4.
>
> Fixes: d1cd3ce900441 (KVM: MMU: check guest CR3 reserved bits based on its physical address width)
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Junaid Shahid <junaids@google.com>
> Cc: Liran Alon <liran.alon@oracle.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> v1 -> v2:
> * remove CR3_PCID_INVD in rsvd when PCIDE is 1 instead of
> removing CR3_PCID_INVD in new_value
>
> arch/x86/kvm/emulate.c | 4 +++-
> arch/x86/kvm/x86.c | 2 +-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index b3705ae..143b7ae 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -4189,7 +4189,9 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
> maxphyaddr = eax & 0xff;
> else
> maxphyaddr = 36;
> - rsvd = rsvd_bits(maxphyaddr, 62);
> + rsvd = rsvd_bits(maxphyaddr, 63);
> + if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)
> + rsvd &= ~CR3_PCID_INVD;
> }
>
> if (new_val & rsvd)
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 87e4805..9a90668 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -863,7 +863,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
> }
>
> if (is_long_mode(vcpu) &&
> - (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 62)))
> + (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
> return 1;
> else if (is_pae(vcpu) && is_paging(vcpu) &&
> !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
>
Reviewed-by: Junaid Shahid <junaids@google.com>
next prev parent reply other threads:[~2018-05-13 15:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-13 9:24 [PATCH v2] KVM: X86: Fix CR3 reserve bits Wanpeng Li
2018-05-13 15:34 ` Junaid Shahid [this message]
2018-05-14 16:14 ` Paolo Bonzini
2018-05-13 11:19 Liran Alon
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=29625752-1e02-dcd7-7b26-1d5c8c30a8db@google.com \
--to=junaids@google.com \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=liran.alon@oracle.com \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.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).