4 files changed, 119 insertions, 0 deletions

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index f5145dcab319..40aab4f5007c 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -261,6 +261,17 @@ struct kvm_mips_tlb {
 	long tlb_lo[2];
 };
 
+#define KVM_NR_MEM_OBJS     4
+
+/*
+ * We don't want allocation failures within the mmu code, so we preallocate
+ * enough memory for a single page fault in a cache.
+ */
+struct kvm_mmu_memory_cache {
+	int nobjs;
+	void *objects[KVM_NR_MEM_OBJS];
+};
+
 #define KVM_MIPS_AUX_FPU	0x1
 #define KVM_MIPS_AUX_MSA	0x2
 
@@ -327,6 +338,9 @@ struct kvm_vcpu_arch {
 	/* Guest ASID of last user mode execution */
 	unsigned int last_user_gasid;
 
+	/* Cache some mmu pages needed inside spinlock regions */
+	struct kvm_mmu_memory_cache mmu_page_cache;
+
 	int last_sched_cpu;
 
 	/* WAIT executed */
@@ -631,6 +645,9 @@ enum kvm_mips_flush {
 	KMF_GPA		= 0x2,
 };
 void kvm_mips_flush_gva_pt(pgd_t *pgd, enum kvm_mips_flush flags);
+void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
+void kvm_trap_emul_invalidate_gva(struct kvm_vcpu *vcpu, unsigned long addr,
+				  bool user);
 extern unsigned long kvm_mips_translate_guest_kseg0_to_hpa(struct kvm_vcpu *vcpu,
 						   unsigned long gva);
 extern void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 1d399396e486..19eaeda6975c 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -864,11 +864,17 @@ static void kvm_mips_invalidate_guest_tlb(struct kvm_vcpu *vcpu,
 	/* No need to flush for entries which are already invalid */
 	if (!((tlb->tlb_lo[0] | tlb->tlb_lo[1]) & ENTRYLO_V))
 		return;
+	/* Don't touch host kernel page tables or TLB mappings */
+	if ((unsigned long)tlb->tlb_hi > 0x7fffffff)
+		return;
 	/* User address space doesn't need flushing for KSeg2/3 changes */
 	user = tlb->tlb_hi < KVM_GUEST_KSEG0;
 
 	preempt_disable();
 
+	/* Invalidate page table entries */
+	kvm_trap_emul_invalidate_gva(vcpu, tlb->tlb_hi & VPN2_MASK, user);
+
 	/*
 	 * Probe the shadow host TLB for the entry being overwritten, if one
 	 * matches, invalidate it
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index a687864de428..c369fdd19fbc 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -396,6 +396,7 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 
 	kvm_mips_dump_stats(vcpu);
 
+	kvm_mmu_free_memory_caches(vcpu);
 	kfree(vcpu->arch.guest_ebase);
 	kfree(vcpu->arch.kseg0_commpage);
 	kfree(vcpu);
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 09146b62552f..dbf2b55ee874 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -14,6 +14,26 @@
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 
+static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
+{
+	while (mc->nobjs)
+		free_page((unsigned long)mc->objects[--mc->nobjs]);
+}
+
+static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
+{
+	void *p;
+
+	BUG_ON(!mc || !mc->nobjs);
+	p = mc->objects[--mc->nobjs];
+	return p;
+}
+
+void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
+{
+	mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+}
+
 static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
 {
 	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
@@ -30,6 +50,56 @@ static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)
 	return cpu_asid(cpu, user_mm);
 }
 
+/**
+ * kvm_mips_walk_pgd() - Walk page table with optional allocation.
+ * @pgd:	Page directory pointer.
+ * @addr:	Address to index page table using.
+ * @cache:	MMU page cache to allocate new page tables from, or NULL.
+ *
+ * Walk the page tables pointed to by @pgd to find the PTE corresponding to the
+ * address @addr. If page tables don't exist for @addr, they will be created
+ * from the MMU cache if @cache is not NULL.
+ *
+ * Returns:	Pointer to pte_t corresponding to @addr.
+ *		NULL if a page table doesn't exist for @addr and !@cache.
+ *		NULL if a page table allocation failed.
+ */
+static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache,
+				unsigned long addr)
+{
+	pud_t *pud;
+	pmd_t *pmd;
+
+	pgd += pgd_index(addr);
+	if (pgd_none(*pgd)) {
+		/* Not used on MIPS yet */
+		BUG();
+		return NULL;
+	}
+	pud = pud_offset(pgd, addr);
+	if (pud_none(*pud)) {
+		pmd_t *new_pmd;
+
+		if (!cache)
+			return NULL;
+		new_pmd = mmu_memory_cache_alloc(cache);
+		pmd_init((unsigned long)new_pmd,
+			 (unsigned long)invalid_pte_table);
+		pud_populate(NULL, pud, new_pmd);
+	}
+	pmd = pmd_offset(pud, addr);
+	if (pmd_none(*pmd)) {
+		pte_t *new_pte;
+
+		if (!cache)
+			return NULL;
+		new_pte = mmu_memory_cache_alloc(cache);
+		clear_page(new_pte);
+		pmd_populate_kernel(NULL, pmd, new_pte);
+	}
+	return pte_offset(pmd, addr);
+}
+
 static int kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)
 {
 	int srcu_idx, err = 0;
@@ -81,6 +151,31 @@ unsigned long kvm_mips_translate_guest_kseg0_to_hpa(struct kvm_vcpu *vcpu,
 	return (kvm->arch.guest_pmap[gfn] << PAGE_SHIFT) + offset;
 }
 
+void kvm_trap_emul_invalidate_gva(struct kvm_vcpu *vcpu, unsigned long addr,
+				  bool user)
+{
+	pgd_t *pgdp;
+	pte_t *ptep;
+
+	addr &= PAGE_MASK << 1;
+
+	pgdp = vcpu->arch.guest_kernel_mm.pgd;
+	ptep = kvm_mips_walk_pgd(pgdp, NULL, addr);
+	if (ptep) {
+		ptep[0] = pfn_pte(0, __pgprot(0));
+		ptep[1] = pfn_pte(0, __pgprot(0));
+	}
+
+	if (user) {
+		pgdp = vcpu->arch.guest_user_mm.pgd;
+		ptep = kvm_mips_walk_pgd(pgdp, NULL, addr);
+		if (ptep) {
+			ptep[0] = pfn_pte(0, __pgprot(0));
+			ptep[1] = pfn_pte(0, __pgprot(0));
+		}
+	}
+}
+
 /*
  * kvm_mips_flush_gva_{pte,pmd,pud,pgd,pt}.
  * Flush a range of guest physical address space from the VM's GPA page tables.