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authorKarimAllah Ahmed <karahmed@amazon.de>2018-01-17 21:18:56 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-30 08:50:22 +0300
commit9445fde8eec02816603e7b12b5d5beb1158cc907 (patch)
tree0e98b1fe67b4d5467cb03216ee75c2481108b198 /virt
parentd805047beb94f9174012465e24e20a222b60ec4d (diff)
downloadlinux-9445fde8eec02816603e7b12b5d5beb1158cc907.tar.xz
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 <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index eaae7252f60c..4f2a2df85b1f 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)