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authorXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>2012-08-21 11:02:51 +0800
committerAvi Kivity <avi@redhat.com>2012-08-22 15:09:03 +0300
commit4d8b81abc47b83a1939e59df2fdb0e98dfe0eedd (patch)
tree47ea77cb4f77a2884a0478ecf84f62e32e5661ee /arch/x86/kvm/mmu.c
parent7068d0971524dd47a38f44f6020ba133432871ca (diff)
KVM: introduce readonly memslot
In current code, if we map a readonly memory space from host to guest and the page is not currently mapped in the host, we will get a fault pfn and async is not allowed, then the vm will crash We introduce readonly memory region to map ROM/ROMD to the guest, read access is happy for readonly memslot, write access on readonly memslot will cause KVM_EXIT_MMIO exit Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
-rw-r--r--arch/x86/kvm/mmu.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5548971ae80..8e312a2e141 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2647,6 +2647,15 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
{
+ /*
+ * Do not cache the mmio info caused by writing the readonly gfn
+ * into the spte otherwise read access on readonly gfn also can
+ * caused mmio page fault and treat it as mmio access.
+ * Return 1 to tell kvm to emulate it.
+ */
+ if (pfn == KVM_PFN_ERR_RO_FAULT)
+ return 1;
+
if (pfn == KVM_PFN_ERR_HWPOISON) {
kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
return 0;