The patch titled
     KVM: MMU: If emulating an instruction fails, try unprotecting the page
has been removed from the -mm tree.  Its filename was
     kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
Subject: KVM: MMU: If emulating an instruction fails, try unprotecting the page
From: Avi Kivity <[EMAIL PROTECTED]>

A page table may have been recycled into a regular page, and so any
instruction can be executed on it.  Unprotect the page and let the cpu do its
thing.

Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---

 drivers/kvm/kvm.h      |    1 
 drivers/kvm/kvm_main.c |    2 +
 drivers/kvm/mmu.c      |   58 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)

diff -puN 
drivers/kvm/kvm.h~kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page
 drivers/kvm/kvm.h
--- 
a/drivers/kvm/kvm.h~kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page
+++ a/drivers/kvm/kvm.h
@@ -450,6 +450,7 @@ unsigned long segment_base(u16 selector)
 
 void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes);
 void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes);
+int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
 
 static inline struct page *_gfn_to_page(struct kvm *kvm, gfn_t gfn)
 {
diff -puN 
drivers/kvm/kvm_main.c~kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page
 drivers/kvm/kvm_main.c
--- 
a/drivers/kvm/kvm_main.c~kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page
+++ a/drivers/kvm/kvm_main.c
@@ -1063,6 +1063,8 @@ int emulate_instruction(struct kvm_vcpu 
        }
 
        if (r) {
+               if (kvm_mmu_unprotect_page_virt(vcpu, cr2))
+                       return EMULATE_DONE;
                if (!vcpu->mmio_needed) {
                        report_emulation_failure(&emulate_ctxt);
                        return EMULATE_FAIL;
diff -puN 
drivers/kvm/mmu.c~kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page
 drivers/kvm/mmu.c
--- 
a/drivers/kvm/mmu.c~kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page
+++ a/drivers/kvm/mmu.c
@@ -478,11 +478,62 @@ static struct kvm_mmu_page *kvm_mmu_get_
        return page;
 }
 
+static void kvm_mmu_page_unlink_children(struct kvm_vcpu *vcpu,
+                                        struct kvm_mmu_page *page)
+{
+       BUG();
+}
+
 static void kvm_mmu_put_page(struct kvm_vcpu *vcpu,
                             struct kvm_mmu_page *page,
                             u64 *parent_pte)
 {
        mmu_page_remove_parent_pte(page, parent_pte);
+       if (page->role.level > PT_PAGE_TABLE_LEVEL)
+               kvm_mmu_page_unlink_children(vcpu, page);
+       hlist_del(&page->hash_link);
+       list_del(&page->link);
+       list_add(&page->link, &vcpu->free_pages);
+}
+
+static void kvm_mmu_zap_page(struct kvm_vcpu *vcpu,
+                            struct kvm_mmu_page *page)
+{
+       u64 *parent_pte;
+
+       while (page->multimapped || page->parent_pte) {
+               if (!page->multimapped)
+                       parent_pte = page->parent_pte;
+               else {
+                       struct kvm_pte_chain *chain;
+
+                       chain = container_of(page->parent_ptes.first,
+                                            struct kvm_pte_chain, link);
+                       parent_pte = chain->parent_ptes[0];
+               }
+               kvm_mmu_put_page(vcpu, page, parent_pte);
+               *parent_pte = 0;
+       }
+}
+
+static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+       unsigned index;
+       struct hlist_head *bucket;
+       struct kvm_mmu_page *page;
+       struct hlist_node *node, *n;
+       int r;
+
+       pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
+       r = 0;
+       index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
+       bucket = &vcpu->kvm->mmu_page_hash[index];
+       hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
+               if (page->gfn == gfn && !page->role.metaphysical) {
+                       kvm_mmu_zap_page(vcpu, page);
+                       r = 1;
+               }
+       return r;
 }
 
 static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa)
@@ -1001,6 +1052,13 @@ void kvm_mmu_post_write(struct kvm_vcpu 
 {
 }
 
+int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
+{
+       gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
+
+       return kvm_mmu_unprotect_page(vcpu, gpa >> PAGE_SHIFT);
+}
+
 static void free_mmu_pages(struct kvm_vcpu *vcpu)
 {
        while (!list_empty(&vcpu->free_pages)) {
_

Patches currently in -mm which might be from [EMAIL PROTECTED] are


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