From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: KarimAllah Ahmed <karahmed@amazon.de>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Subject: Re: [PATCH] KVM/nVMX: Do not validate that posted_intr_desc_addr is page aligned
Date: Wed, 24 Oct 2018 13:17:19 +0200 [thread overview]
Message-ID: <20181024111718.GB2221@potion.hotspot.internet-for-guests.com> (raw)
In-Reply-To: <20181024110109.GA15991@linux.intel.com>
2018-10-24 04:01-0700, Sean Christopherson:
> On Sat, Oct 20, 2018 at 11:42:59PM +0200, KarimAllah Ahmed wrote:
> > The spec only requires the posted interrupt descriptor address to be
> > 64-bytes aligned (i.e. bits[0:5] == 0). Using page_address_valid also
> > forces the address to be page aligned.
> >
> > Only validate that the address does not cross the maximum physical address
> > without enforcing a page alignment.
> >
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Cc: Radim Krčmář <rkrcmar@redhat.com>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Borislav Petkov <bp@alien8.de>
> > Cc: H. Peter Anvin <hpa@zytor.com>
> > Cc: x86@kernel.org
> > Cc: kvm@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > Fixes: 6de84e581c0 ("nVMX x86: check posted-interrupt descriptor addresss on vmentry of L2")
> > Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
> > ---
> > arch/x86/kvm/vmx.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > index 30bf860..47962f2 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -11668,7 +11668,7 @@ static int nested_vmx_check_apicv_controls(struct kvm_vcpu *vcpu,
> > !nested_exit_intr_ack_set(vcpu) ||
> > (vmcs12->posted_intr_nv & 0xff00) ||
> > (vmcs12->posted_intr_desc_addr & 0x3f) ||
> > - (!page_address_valid(vcpu, vmcs12->posted_intr_desc_addr))))
> > + (vmcs12->posted_intr_desc_addr >> cpuid_maxphyaddr(vcpu)))
> > return -EINVAL;
>
> Can you update the comment for this code block? It has a stale blurb
> about "the descriptor address has been already checked in
> nested_get_vmcs12_pages" and it'd be nice to state why bits[5:0] must
> be zero (your changelog is much more helpful than the current comment).
>
> With that:
>
> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
I have just sent a pull request with the stale comment. :(
prev parent reply other threads:[~2018-10-24 11:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-20 21:42 [PATCH] KVM/nVMX: Do not validate that posted_intr_desc_addr is page aligned KarimAllah Ahmed
2018-10-20 22:50 ` [PATCH v2] " KarimAllah Ahmed
2018-10-22 17:12 ` Jim Mattson
2018-10-22 23:23 ` Krish Sadhukhan
2018-10-24 11:01 ` [PATCH] " Sean Christopherson
2018-10-24 11:17 ` Radim Krčmář [this message]
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