From: KarimAllah Ahmed Date: Wed, 17 Jan 2018 18:18:56 +0000 (+0100) Subject: kvm: Map PFN-type memory regions as writable (if possible) X-Git-Tag: v4.9.104~263 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9445fde8eec02816603e7b12b5d5beb1158cc907;p=thirdparty%2Fkernel%2Fstable.git kvm: Map PFN-type memory regions as writable (if possible) [ Upstream commit a340b3e229b24a56f1c7f5826b15a3af0f4b13e5 ] 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 Cc: Radim Krčmář Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: KarimAllah Ahmed Reviewed-by: Paolo Bonzini Signed-off-by: Radim Krčmář Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index eaae7252f60c2..4f2a2df85b1f5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1466,7 +1466,8 @@ static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault) static int hva_to_pfn_remapped(struct vm_area_struct *vma, unsigned long addr, bool *async, - bool write_fault, kvm_pfn_t *p_pfn) + bool write_fault, bool *writable, + kvm_pfn_t *p_pfn) { unsigned long pfn; int r; @@ -1492,6 +1493,8 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma, } + if (writable) + *writable = true; /* * Get a reference here because callers of *hva_to_pfn* and @@ -1557,7 +1560,7 @@ retry: if (vma == NULL) pfn = KVM_PFN_ERR_FAULT; else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) { - r = hva_to_pfn_remapped(vma, addr, async, write_fault, &pfn); + r = hva_to_pfn_remapped(vma, addr, async, write_fault, writable, &pfn); if (r == -EAGAIN) goto retry; if (r < 0)