[PATCH v2] KVM/nVMX: Do not validate that posted_intr_desc_addr is page aligned

From: KarimAllah Ahmed
Date: Sat Oct 20 2018 - 19:01:29 EST

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.

v1 -> v2:
- Add a missing parenthesis (dropped while merging!)

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Fixes: 6de84e581c0 ("nVMX x86: check posted-interrupt descriptor addresss on vmentry of L2")
Signed-off-by: KarimAllah Ahmed <karahmed@xxxxxxxxx>
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 38f1a16..bb0fcdb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11667,7 +11667,7 @@ 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;

/* tpr shadow is needed by all apicv features. */