6 files changed, 95 insertions, 15 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b1ed0a1..b666d8d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -32,6 +32,7 @@
 #include <linux/compiler.h>
 #include <linux/srcu.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include <asm/page.h>
 #include <asm/cmpxchg.h>
@@ -1960,6 +1961,27 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
 	return pt_write;
 }
 
+static void kvm_send_hwpoison_signal(struct kvm *kvm, gfn_t gfn)
+{
+	char buf[1];
+	void __user *hva;
+	int r;
+
+	/* Touch the page, so send SIGBUS */
+	hva = (void __user *)gfn_to_hva(kvm, gfn);
+	r = copy_from_user(buf, hva, 1);
+}
+
+static int kvm_handle_bad_page(struct kvm *kvm, gfn_t gfn, pfn_t pfn)
+{
+	kvm_release_pfn_clean(pfn);
+	if (is_hwpoison_pfn(pfn)) {
+		kvm_send_hwpoison_signal(kvm, gfn);
+		return 0;
+	}
+	return 1;
+}
+
 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
 {
 	int r;
@@ -1983,10 +2005,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
 	pfn = gfn_to_pfn(vcpu->kvm, gfn);
 
 	/* mmio */
-	if (is_error_pfn(pfn)) {
-		kvm_release_pfn_clean(pfn);
-		return 1;
-	}
+	if (is_error_pfn(pfn))
+		return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
 
 	spin_lock(&vcpu->kvm->mmu_lock);
 	if (mmu_notifier_retry(vcpu, mmu_seq))
@@ -2198,10 +2218,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
 	mmu_seq = vcpu->kvm->mmu_notifier_seq;
 	smp_rmb();
 	pfn = gfn_to_pfn(vcpu->kvm, gfn);
-	if (is_error_pfn(pfn)) {
-		kvm_release_pfn_clean(pfn);
-		return 1;
-	}
+	if (is_error_pfn(pfn))
+		return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
 	spin_lock(&vcpu->kvm->mmu_lock);
 	if (mmu_notifier_retry(vcpu, mmu_seq))
 		goto out_unlock;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 2331bdc..c7f2777 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -431,11 +431,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
 	pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
 
 	/* mmio */
-	if (is_error_pfn(pfn)) {
-		pgprintk("gfn %lx is mmio\n", walker.gfn);
-		kvm_release_pfn_clean(pfn);
-		return 1;
-	}
+	if (is_error_pfn(pfn))
+		return kvm_handle_bad_page(vcpu->kvm, walker.gfn, pfn);
 
 	spin_lock(&vcpu->kvm->mmu_lock);
 	if (mmu_notifier_retry(vcpu, mmu_seq))
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7cb116a..a0e0197 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -266,6 +266,7 @@ extern pfn_t bad_pfn;
 
 int is_error_page(struct page *page);
 int is_error_pfn(pfn_t pfn);
+int is_hwpoison_pfn(pfn_t pfn);
 int kvm_is_error_hva(unsigned long addr);
 int kvm_set_memory_region(struct kvm *kvm,
 			  struct kvm_userspace_memory_region *mem,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a2b4804..7a9ab7d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1465,6 +1465,14 @@ extern int sysctl_memory_failure_recovery;
 extern void shake_page(struct page *p, int access);
 extern atomic_long_t mce_bad_pages;
 extern int soft_offline_page(struct page *page, int flags);
+#ifdef CONFIG_MEMORY_FAILURE
+int is_hwpoison_address(unsigned long addr);
+#else
+static inline int is_hwpoison_address(unsigned long addr)
+{
+	return 0;
+}
+#endif
 
 extern void dump_page(struct page *page);
 
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 620b0b4..378b0f6 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -45,6 +45,7 @@
 #include <linux/page-isolation.h>
 #include <linux/suspend.h>
 #include <linux/slab.h>
+#include <linux/swapops.h>
 #include "internal.h"
 
 int sysctl_memory_failure_early_kill __read_mostly = 0;
@@ -1296,3 +1297,32 @@ done:
 	/* keep elevated page count for bad page */
 	return ret;
 }
+
+int is_hwpoison_address(unsigned long addr)
+{
+	pgd_t *pgdp;
+	pud_t pud, *pudp;
+	pmd_t pmd, *pmdp;
+	pte_t pte, *ptep;
+	swp_entry_t entry;
+
+	pgdp = pgd_offset(current->mm, addr);
+	if (!pgd_present(*pgdp))
+		return 0;
+	pudp = pud_offset(pgdp, addr);
+	pud = *pudp;
+	if (!pud_present(pud) || pud_large(pud))
+		return 0;
+	pmdp = pmd_offset(pudp, addr);
+	pmd = *pmdp;
+	if (!pmd_present(pmd) || pmd_large(pmd))
+		return 0;
+	ptep = pte_offset_map(pmdp, addr);
+	pte = *ptep;
+	pte_unmap(ptep);
+	if (!is_swap_pte(pte))
+		return 0;
+	entry = pte_to_swp_entry(pte);
+	return is_hwpoison_entry(entry);
+}
+EXPORT_SYMBOL_GPL(is_hwpoison_address);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f032806..187aa8d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -92,6 +92,9 @@ static bool kvm_rebooting;
 
 static bool largepages_enabled = true;
 
+struct page *hwpoison_page;
+pfn_t hwpoison_pfn;
+
 inline int kvm_is_mmio_pfn(pfn_t pfn)
 {
 	if (pfn_valid(pfn)) {
@@ -810,16 +813,22 @@ EXPORT_SYMBOL_GPL(kvm_disable_largepages);
 
 int is_error_page(struct page *page)
 {
-	return page == bad_page;
+	return page == bad_page || page == hwpoison_page;
 }
 EXPORT_SYMBOL_GPL(is_error_page);
 
 int is_error_pfn(pfn_t pfn)
 {
-	return pfn == bad_pfn;
+	return pfn == bad_pfn || pfn == hwpoison_pfn;
 }
 EXPORT_SYMBOL_GPL(is_error_pfn);
 
+int is_hwpoison_pfn(pfn_t pfn)
+{
+	return pfn == hwpoison_pfn;
+}
+EXPORT_SYMBOL_GPL(is_hwpoison_pfn);
+
 static inline unsigned long bad_hva(void)
 {
 	return PAGE_OFFSET;
@@ -945,6 +954,11 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr)
 	if (unlikely(npages != 1)) {
 		struct vm_area_struct *vma;
 
+		if (is_hwpoison_address(addr)) {
+			get_page(hwpoison_page);
+			return page_to_pfn(hwpoison_page);
+		}
+
 		down_read(&current->mm->mmap_sem);
 		vma = find_vma(current->mm, addr);
 
@@ -2197,6 +2211,15 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 
 	bad_pfn = page_to_pfn(bad_page);
 
+	hwpoison_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+
+	if (hwpoison_page == NULL) {
+		r = -ENOMEM;
+		goto out_free_0;
+	}
+
+	hwpoison_pfn = page_to_pfn(hwpoison_page);
+
 	if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
 		r = -ENOMEM;
 		goto out_free_0;
@@ -2269,6 +2292,8 @@ out_free_1:
 out_free_0a:
 	free_cpumask_var(cpus_hardware_enabled);
 out_free_0:
+	if (hwpoison_page)
+		__free_page(hwpoison_page);
 	__free_page(bad_page);
 out:
 	kvm_arch_exit();
@@ -2290,6 +2315,7 @@ void kvm_exit(void)
 	kvm_arch_hardware_unsetup();
 	kvm_arch_exit();
 	free_cpumask_var(cpus_hardware_enabled);
+	__free_page(hwpoison_page);
 	__free_page(bad_page);
 }
 EXPORT_SYMBOL_GPL(kvm_exit);