On 02/05/2018 11:26 PM, Jim Mattson wrote:

On Mon, Feb 5, 2018 at 10:48 AM KarimAllah Ahmed [off-list ref] wrote:

quoted

@@ -5264,9 +5264,8 @@ static void

vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)

quoted

          max_irr = find_last_bit((unsigned long

*)vmx->nested.pi_desc->pir, 256);

quoted

          if (max_irr != 256) {
-               vapic_page = kmap(vmx->nested.virtual_apic_page);
+               vapic_page = vmx->nested.virtual_apic_mapping.kaddr;
                  __kvm_apic_update_irr(vmx->nested.pi_desc->pir,

vapic_page);

quoted

-               kunmap(vmx->nested.virtual_apic_page);

Your kernel mapping now survives exits to userspace. I didn't think that
was kosher, but I'd be happy to hear that I'm wrong.

Can you elaborate a bit? I do not really understand what is the concern.

quoted

@@ -7502,10 +7501,8 @@ static void free_nested(struct vcpu_vmx *vmx)
          /* Unpin physical memory we referred to in the vmcs02 */
          if (vmx->nested.apic_access_mapping.pfn)

kvm_release_host_mapping(&vmx->nested.apic_access_mapping, true);

quoted

-       if (vmx->nested.virtual_apic_page) {
-               kvm_release_page_dirty(vmx->nested.virtual_apic_page);
-               vmx->nested.virtual_apic_page = NULL;
-       }
+       if (vmx->nested.virtual_apic_mapping.pfn)
+

kvm_release_host_mapping(&vmx->nested.virtual_apic_mapping, true);

Is the host PFN guaranteed to be non-zero?

Yeah, I should not have assumed that PFN zero is invalid. Will fix.
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