From: Sean Christopherson <sean.j.christopherson@intel.com>
To: KarimAllah Ahmed <karahmed@amazon.de>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@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 04:01:09 -0700 [thread overview]
Message-ID: <20181024110109.GA15991@linux.intel.com> (raw)
In-Reply-To: <1540071779-20848-1-git-send-email-karahmed@amazon.de>
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>
>
> /* tpr shadow is needed by all apicv features. */
> --
> 2.7.4
>
next prev parent reply other threads:[~2018-10-24 11:01 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 ` Sean Christopherson [this message]
2018-10-24 11:17 ` [PATCH] " Radim Krčmář
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