For EPT-violations that are triggered by a read, the pages are also mapped with
write permissions (if their memory region is also writable). That would avoid
getting yet another fault on the same page when a write occurs.

This optimization only happens when you have a "struct page" backing the memory
region. So also enable it for memory regions that do not have a "struct page".

Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Radim Krčmář <rkrc...@redhat.com>
Cc: k...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: KarimAllah Ahmed <karah...@amazon.de>
---
 virt/kvm/kvm_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 97da45e..0efb089 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1534,6 +1534,8 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool 
atomic, bool *async,
                        goto retry;
                if (r < 0)
                        pfn = KVM_PFN_ERR_FAULT;
+               if (writable)
+                       *writable = true;
        } else {
                if (async && vma_is_valid(vma, write_fault))
                        *async = true;
-- 
2.7.4

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