[patch 0/6] pv mmu fixes

[patch 0/6] pv mmu fixes

[Marcelo Tosatti]

The following patchset fixes pvmmu/cr3-cache for 32-bit guests.


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[patch 1/6] KVM: pvmmu: handle ptes in highmem

[Marcelo Tosatti]

[-- Attachment #1: kvm-mmu-highpte --]
[-- Type: text/plain, Size: 1434 bytes --]

Find the physical address through kmap_atomic_to_page().

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.first/arch/x86/kernel/kvm.c
===================================================================
--- kvm.first.orig/arch/x86/kernel/kvm.c
+++ kvm.first/arch/x86/kernel/kvm.c
@@ -26,6 +26,7 @@
 #include <linux/cpu.h>
 #include <linux/mm.h>
 #include <linux/hardirq.h>
+#include <linux/highmem.h>
 #include <asm/tlbflush.h>
 #include <asm/asm.h>
 
@@ -205,11 +206,23 @@ static void __init setup_guest_cr3_cache
 
 static void kvm_mmu_write(void *dest, u64 val)
 {
-	struct kvm_mmu_op_write_pte wpte = {
-		.header.op = KVM_MMU_OP_WRITE_PTE,
-		.pte_phys = (unsigned long)__pa(dest),
-		.pte_val = val,
-	};
+	__u64 pte_phys;
+	struct kvm_mmu_op_write_pte wpte;
+
+#ifdef CONFIG_HIGHPTE
+	struct page *page;
+	unsigned long dst = (unsigned long) dest;
+
+	page = kmap_atomic_to_page(dest);
+	pte_phys = page_to_pfn(page);
+	pte_phys <<= PAGE_SHIFT;
+	pte_phys += (dst & ~(PAGE_MASK));
+#else
+	pte_phys = (unsigned long)__pa(dest);
+#endif
+	wpte.header.op = KVM_MMU_OP_WRITE_PTE;
+	wpte.pte_val = val;
+	wpte.pte_phys = pte_phys;
 
 	kvm_deferred_mmu_op(&wpte, sizeof wpte);
 }

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[patch 2/6] KVM: pvmmu: hook set_pud for 3-level pagetables

[Marcelo Tosatti]

[-- Attachment #1: kvm-fix-32 --]
[-- Type: text/plain, Size: 1445 bytes --]

The paravirt interface will export set_pud for 3-level pagetables. Hook it.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.first/arch/x86/kernel/kvm.c
===================================================================
--- kvm.first.orig/arch/x86/kernel/kvm.c
+++ kvm.first/arch/x86/kernel/kvm.c
@@ -296,15 +296,17 @@ static void kvm_pmd_clear(pmd_t *pmdp)
 }
 #endif
 
-static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
+static void kvm_set_pud(pud_t *pudp, pud_t pud)
 {
-	kvm_mmu_write(pgdp, pgd_val(pgd));
+	kvm_mmu_write(pudp, pud_val(pud));
 }
 
-static void kvm_set_pud(pud_t *pudp, pud_t pud)
+#if PAGETABLE_LEVELS == 4
+static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
 {
-	kvm_mmu_write(pudp, pud_val(pud));
+	kvm_mmu_write(pgdp, pgd_val(pgd));
 }
+#endif
 #endif /* PAGETABLE_LEVELS >= 3 */
 
 static void kvm_flush_tlb(void)
@@ -363,8 +365,10 @@ static void paravirt_ops_setup(void)
 		pv_mmu_ops.pmd_clear = kvm_pmd_clear;
 #endif
 		pv_mmu_ops.set_pud = kvm_set_pud;
+#if PAGETABLE_LEVELS == 4
 		pv_mmu_ops.set_pgd = kvm_set_pgd;
 #endif
+#endif
 		pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
 		pv_mmu_ops.release_pt = kvm_release_pt;
 		pv_mmu_ops.release_pd = kvm_release_pt;

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[patch 3/6] KVM: pvmmu: kvm_write_cr3() inline asm fix

[Marcelo Tosatti]

[-- Attachment #1: cr3-register --]
[-- Type: text/plain, Size: 843 bytes --]

Let the compiler choose register placing. All we care is that "trap" 
value gets retained.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.first/arch/x86/kernel/kvm.c
===================================================================
--- kvm.first.orig/arch/x86/kernel/kvm.c
+++ kvm.first/arch/x86/kernel/kvm.c
@@ -138,7 +138,7 @@ static void kvm_write_cr3(unsigned long 
 				_ASM_EXTABLE(0b, 2b)
 				: "=&r" (trap)
 				: "n" (1UL), "n" (0UL),
-				  "b" (cache->entry[idx].host_cr3),
+				  "r" (cache->entry[idx].host_cr3),
 				  "m" (__force_order));
 			if (!trap)
 				goto out;

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[patch 4/6] KVM: pvmmu: fix mmu_alloc_roots() typo

[Marcelo Tosatti]

[-- Attachment #1: fix-mmu-alloc-roots --]
[-- Type: text/plain, Size: 849 bytes --]

Slipped through on the first patch.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.first/arch/x86/kvm/mmu.c
===================================================================
--- kvm.first.orig/arch/x86/kvm/mmu.c
+++ kvm.first/arch/x86/kvm/mmu.c
@@ -1321,7 +1321,7 @@ static void mmu_alloc_roots(struct kvm_v
 		ASSERT(!VALID_PAGE(root));
 		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
 			if (!is_present_pte(vcpu->arch.pdptrs[i])) {
-				vcpu->arch.mmu.pae_root[i] = 0;
+				vcpu->arch.mmu.pae_root[j][i] = 0;
 				continue;
 			}
 			root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;

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[patch 5/6] KVM: pvmmu: kvm_patch might be called after initialization

[Marcelo Tosatti]

[-- Attachment #1: fix-cr3-cache --]
[-- Type: text/plain, Size: 837 bytes --]

kvm_patch might be called during module load.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.first/arch/x86/kernel/kvm.c
===================================================================
--- kvm.first.orig/arch/x86/kernel/kvm.c
+++ kvm.first/arch/x86/kernel/kvm.c
@@ -184,7 +184,7 @@ static void register_cr3_cache(void *cac
 	wrmsrl(KVM_MSR_SET_CR3_CACHE, __pa(&state->cr3_cache));
 }
 
-static unsigned __init kvm_patch(u8 type, u16 clobbers, void *ibuf,
+static unsigned kvm_patch(u8 type, u16 clobbers, void *ibuf,
 				 unsigned long addr, unsigned len)
 {
 	switch (type) {

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[patch 6/6] KVM: pvmmu: cache pdptrs

[Marcelo Tosatti]

[-- Attachment #1: cache-pdptrs --]
[-- Type: text/plain, Size: 6425 bytes --]

The pdptrs need to be cached in addition to the shadowed root tables, so 
the guest walk can be done properly.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.first/arch/x86/kvm/mmu.c
===================================================================
--- kvm.first.orig/arch/x86/kvm/mmu.c
+++ kvm.first/arch/x86/kvm/mmu.c
@@ -1320,11 +1320,11 @@ static void mmu_alloc_roots(struct kvm_v
 
 		ASSERT(!VALID_PAGE(root));
 		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
-			if (!is_present_pte(vcpu->arch.pdptrs[i])) {
+			if (!is_present_pte(vcpu->arch.pdptrs[j][i])) {
 				vcpu->arch.mmu.pae_root[j][i] = 0;
 				continue;
 			}
-			root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
+			root_gfn = vcpu->arch.pdptrs[j][i] >> PAGE_SHIFT;
 		} else if (vcpu->arch.mmu.root_level == 0)
 			root_gfn = 0;
 		sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
Index: kvm.first/arch/x86/kvm/paging_tmpl.h
===================================================================
--- kvm.first.orig/arch/x86/kvm/paging_tmpl.h
+++ kvm.first/arch/x86/kvm/paging_tmpl.h
@@ -136,7 +136,8 @@ walk:
 	pte = vcpu->arch.cr3;
 #if PTTYPE == 64
 	if (!is_long_mode(vcpu)) {
-		pte = vcpu->arch.pdptrs[(addr >> 30) & 3];
+		pte = vcpu->arch.pdptrs[vcpu->arch.cr3_cache_idx]
+				       [(addr >> 30) & 3];
 		if (!is_present_pte(pte))
 			goto not_present;
 		--walker->level;
Index: kvm.first/arch/x86/kvm/x86.c
===================================================================
--- kvm.first.orig/arch/x86/kvm/x86.c
+++ kvm.first/arch/x86/kvm/x86.c
@@ -192,13 +192,21 @@ static void __queue_exception(struct kvm
 /*
  * Load the pae pdptrs.  Return true is they are all valid.
  */
-int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
+int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3, int cr3_cache_inc)
 {
 	gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT;
 	unsigned offset = ((cr3 & (PAGE_SIZE-1)) >> 5) << 2;
 	int i;
 	int ret;
-	u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
+	u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs[0])];
+	int idx = vcpu->arch.cr3_cache_idx;
+
+	idx++;
+	if (unlikely(idx >= vcpu->arch.cr3_cache_limit))
+		idx = 0;
+
+	if (cr3_cache_inc)
+		vcpu->arch.cr3_cache_idx = idx;
 
 	down_read(&vcpu->kvm->slots_lock);
 	ret = kvm_read_guest_page(vcpu->kvm, pdpt_gfn, pdpte,
@@ -215,7 +223,7 @@ int load_pdptrs(struct kvm_vcpu *vcpu, u
 	}
 	ret = 1;
 
-	memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
+	memcpy(vcpu->arch.pdptrs[idx], pdpte, sizeof(vcpu->arch.pdptrs[0]));
 out:
 	up_read(&vcpu->kvm->slots_lock);
 
@@ -225,7 +233,7 @@ EXPORT_SYMBOL_GPL(load_pdptrs);
 
 static bool pdptrs_changed(struct kvm_vcpu *vcpu)
 {
-	u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
+	u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs[0])];
 	bool changed = true;
 	int r;
 
@@ -236,7 +244,8 @@ static bool pdptrs_changed(struct kvm_vc
 	r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
 	if (r < 0)
 		goto out;
-	changed = memcmp(pdpte, vcpu->arch.pdptrs, sizeof(pdpte)) != 0;
+	changed = memcmp(pdpte, vcpu->arch.pdptrs[vcpu->arch.cr3_cache_idx],
+			 sizeof(pdpte)) != 0;
 out:
 	up_read(&vcpu->kvm->slots_lock);
 
@@ -286,7 +295,7 @@ void kvm_set_cr0(struct kvm_vcpu *vcpu, 
 			}
 		} else
 #endif
-		if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->arch.cr3)) {
+		if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->arch.cr3, 1)) {
 			printk(KERN_DEBUG "set_cr0: #GP, pdptrs "
 			       "reserved bits\n");
 			kvm_inject_gp(vcpu, 0);
@@ -325,7 +334,7 @@ void kvm_set_cr4(struct kvm_vcpu *vcpu, 
 			return;
 		}
 	} else if (is_paging(vcpu) && !is_pae(vcpu) && (cr4 & X86_CR4_PAE)
-		   && !load_pdptrs(vcpu, vcpu->arch.cr3)) {
+		   && !load_pdptrs(vcpu, vcpu->arch.cr3, 1)) {
 		printk(KERN_DEBUG "set_cr4: #GP, pdptrs reserved bits\n");
 		kvm_inject_gp(vcpu, 0);
 		return;
@@ -363,7 +372,7 @@ void kvm_set_cr3(struct kvm_vcpu *vcpu, 
 				kvm_inject_gp(vcpu, 0);
 				return;
 			}
-			if (is_paging(vcpu) && !load_pdptrs(vcpu, cr3)) {
+			if (is_paging(vcpu) && !load_pdptrs(vcpu, cr3, 0)) {
 				printk(KERN_DEBUG "set_cr3: #GP, pdptrs "
 				       "reserved bits\n");
 				kvm_inject_gp(vcpu, 0);
@@ -3047,7 +3056,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct
 	mmu_reset_needed |= vcpu->arch.cr4 != sregs->cr4;
 	kvm_x86_ops->set_cr4(vcpu, sregs->cr4);
 	if (!is_long_mode(vcpu) && is_pae(vcpu))
-		load_pdptrs(vcpu, vcpu->arch.cr3);
+		load_pdptrs(vcpu, vcpu->arch.cr3, 1);
 
 	if (mmu_reset_needed)
 		kvm_mmu_reset_context(vcpu);
Index: kvm.first/include/asm-x86/kvm_host.h
===================================================================
--- kvm.first.orig/include/asm-x86/kvm_host.h
+++ kvm.first/include/asm-x86/kvm_host.h
@@ -211,7 +211,7 @@ struct kvm_vcpu_arch {
 	unsigned int cr3_cache_limit;
 	unsigned long cr4;
 	unsigned long cr8;
-	u64 pdptrs[4]; /* pae */
+	u64 pdptrs[KVM_CR3_CACHE_SIZE][4]; /* pae */
 	u64 shadow_efer;
 	u64 apic_base;
 	struct kvm_lapic *apic;    /* kernel irqchip context */
@@ -433,7 +433,7 @@ void kvm_mmu_zap_all(struct kvm *kvm);
 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm);
 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
 
-int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
+int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3, int cr3_cache_inc);
 
 int __emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
 			  const void *val, int bytes);
@@ -526,7 +526,6 @@ int kvm_mmu_page_fault(struct kvm_vcpu *
 
 void kvm_enable_tdp(void);
 
-int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
 int complete_pio(struct kvm_vcpu *vcpu);
 
 static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
Index: kvm.first/arch/x86/kvm/svm.c
===================================================================
--- kvm.first.orig/arch/x86/kvm/svm.c
+++ kvm.first/arch/x86/kvm/svm.c
@@ -1394,7 +1394,7 @@ static int handle_exit(struct kvm_run *k
 		vcpu->arch.cr0 = svm->vmcb->save.cr0;
 		vcpu->arch.cr3 = svm->vmcb->save.cr3;
 		if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
-			if (!load_pdptrs(vcpu, vcpu->arch.cr3)) {
+			if (!load_pdptrs(vcpu, vcpu->arch.cr3, 1)) {
 				kvm_inject_gp(vcpu, 0);
 				return 1;
 			}

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Re: [patch 0/6] pv mmu fixes

[Avi Kivity]

Marcelo Tosatti wrote:
> The following patchset fixes pvmmu/cr3-cache for 32-bit guests.
>
>
>   
Thanks.  I folded the fixes into the patches they fixed, and merged 
everything except cr3 cache (I want to look at it again and see if I can 
reduce the impact a little).  pvmmu branch now contains the unmerged 
patches.

-- 
error compiling committee.c: too many arguments to function


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