Merge branch 'queue' into next

* queue:
  KVM: MMU: Eliminate pointless temporary 'ac'
  KVM: MMU: Avoid access/dirty update loop if all is well
  KVM: MMU: Eliminate eperm temporary
  KVM: MMU: Optimize is_last_gpte()
  KVM: MMU: Simplify walk_addr_generic() loop
  KVM: MMU: Optimize pte permission checks
  KVM: MMU: Update accessed and dirty bits after guest pagetable walk
  KVM: MMU: Move gpte_access() out of paging_tmpl.h
  KVM: MMU: Optimize gpte_access() slightly
  KVM: MMU: Push clean gpte write protection out of gpte_access()
  KVM: clarify kvmclock documentation
  KVM: make processes waiting on vcpu mutex killable
  KVM: SVM: Make use of asm.h
  KVM: VMX: Make use of asm.h
  KVM: VMX: Make lto-friendly

Signed-off-by: Avi Kivity <avi@redhat.com>

Documentation/virtual/kvm/msr.txt

@@ -34,9 +34,12 @@ MSR_KVM_WALL_CLOCK_NEW:   0x4b564d00
 		time information and check that they are both equal and even.
 		An odd version indicates an in-progress update.
 
-		sec: number of seconds for wallclock.
+		sec: number of seconds for wallclock at time of boot.
 
-		nsec: number of nanoseconds for wallclock.
+		nsec: number of nanoseconds for wallclock at time of boot.
+
+	In order to get the current wallclock time, the system_time from
+	MSR_KVM_SYSTEM_TIME_NEW needs to be added.
 
 	Note that although MSRs are per-CPU entities, the effect of this
 	particular MSR is global.
@@ -82,20 +85,25 @@ MSR_KVM_SYSTEM_TIME_NEW:  0x4b564d01
 		time at the time this structure was last updated. Unit is
 		nanoseconds.
 
-		tsc_to_system_mul: a function of the tsc frequency. One has
-		to multiply any tsc-related quantity by this value to get
-		a value in nanoseconds, besides dividing by 2^tsc_shift
+		tsc_to_system_mul: multiplier to be used when converting
+		tsc-related quantity to nanoseconds
 
-		tsc_shift: cycle to nanosecond divider, as a power of two, to
-		allow for shift rights. One has to shift right any tsc-related
-		quantity by this value to get a value in nanoseconds, besides
-		multiplying by tsc_to_system_mul.
+		tsc_shift: shift to be used when converting tsc-related
+		quantity to nanoseconds. This shift will ensure that
+		multiplication with tsc_to_system_mul does not overflow.
+		A positive value denotes a left shift, a negative value
+		a right shift.
 
-		With this information, guests can derive per-CPU time by
-		doing:
+		The conversion from tsc to nanoseconds involves an additional
+		right shift by 32 bits. With this information, guests can
+		derive per-CPU time by doing:
 
 			time = (current_tsc - tsc_timestamp)
-			time = (time * tsc_to_system_mul) >> tsc_shift
+			if (tsc_shift >= 0)
+				time <<= tsc_shift;
+			else
+				time >>= -tsc_shift;
+			time = (time * tsc_to_system_mul) >> 32
 			time = time + system_time
 
 		flags: bits in this field indicate extended capabilities

arch/x86/include/asm/kvm_host.h

@@ -287,10 +287,24 @@ struct kvm_mmu {
 	union kvm_mmu_page_role base_role;
 	bool direct_map;
 
+	/*
+	 * Bitmap; bit set = permission fault
+	 * Byte index: page fault error code [4:1]
+	 * Bit index: pte permissions in ACC_* format
+	 */
+	u8 permissions[16];
+
 	u64 *pae_root;
 	u64 *lm_root;
 	u64 rsvd_bits_mask[2][4];
 
+	/*
+	 * Bitmap: bit set = last pte in walk
+	 * index[0:1]: level (zero-based)
+	 * index[2]: pte.ps
+	 */
+	u8 last_pte_bitmap;
+
 	bool nx;
 
 	u64 pdptrs[4]; /* pae */

arch/x86/kvm/mmu.c

@@ -3408,6 +3408,18 @@ static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
 	return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
 }
 
+static inline void protect_clean_gpte(unsigned *access, unsigned gpte)
+{
+	unsigned mask;
+
+	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);
+
+	mask = (unsigned)~ACC_WRITE_MASK;
+	/* Allow write access to dirty gptes */
+	mask |= (gpte >> (PT_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) & PT_WRITABLE_MASK;
+	*access &= mask;
+}
+
 static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access,
 			   int *nr_present)
 {
@@ -3425,6 +3437,25 @@ static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access,
 	return false;
 }
 
+static inline unsigned gpte_access(struct kvm_vcpu *vcpu, u64 gpte)
+{
+	unsigned access;
+
+	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
+	access &= ~(gpte >> PT64_NX_SHIFT);
+
+	return access;
+}
+
+static inline bool is_last_gpte(struct kvm_mmu *mmu, unsigned level, unsigned gpte)
+{
+	unsigned index;
+
+	index = level - 1;
+	index |= (gpte & PT_PAGE_SIZE_MASK) >> (PT_PAGE_SIZE_SHIFT - 2);
+	return mmu->last_pte_bitmap & (1 << index);
+}
+
 #define PTTYPE 64
 #include "paging_tmpl.h"
 #undef PTTYPE
@@ -3494,6 +3525,56 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
 	}
 }
 
+static void update_permission_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
+{
+	unsigned bit, byte, pfec;
+	u8 map;
+	bool fault, x, w, u, wf, uf, ff, smep;
+
+	smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
+	for (byte = 0; byte < ARRAY_SIZE(mmu->permissions); ++byte) {
+		pfec = byte << 1;
+		map = 0;
+		wf = pfec & PFERR_WRITE_MASK;
+		uf = pfec & PFERR_USER_MASK;
+		ff = pfec & PFERR_FETCH_MASK;
+		for (bit = 0; bit < 8; ++bit) {
+			x = bit & ACC_EXEC_MASK;
+			w = bit & ACC_WRITE_MASK;
+			u = bit & ACC_USER_MASK;
+
+			/* Not really needed: !nx will cause pte.nx to fault */
+			x |= !mmu->nx;
+			/* Allow supervisor writes if !cr0.wp */
+			w |= !is_write_protection(vcpu) && !uf;
+			/* Disallow supervisor fetches of user code if cr4.smep */
+			x &= !(smep && u && !uf);
+
+			fault = (ff && !x) || (uf && !u) || (wf && !w);
+			map |= fault << bit;
+		}
+		mmu->permissions[byte] = map;
+	}
+}
+
+static void update_last_pte_bitmap(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
+{
+	u8 map;
+	unsigned level, root_level = mmu->root_level;
+	const unsigned ps_set_index = 1 << 2;  /* bit 2 of index: ps */
+
+	if (root_level == PT32E_ROOT_LEVEL)
+		--root_level;
+	/* PT_PAGE_TABLE_LEVEL always terminates */
+	map = 1 | (1 << ps_set_index);
+	for (level = PT_DIRECTORY_LEVEL; level <= root_level; ++level) {
+		if (level <= PT_PDPE_LEVEL
+		    && (mmu->root_level >= PT32E_ROOT_LEVEL || is_pse(vcpu)))
+			map |= 1 << (ps_set_index | (level - 1));
+	}
+	mmu->last_pte_bitmap = map;
+}
+
 static int paging64_init_context_common(struct kvm_vcpu *vcpu,
 					struct kvm_mmu *context,
 					int level)
@@ -3502,6 +3583,8 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu,
 	context->root_level = level;
 
 	reset_rsvds_bits_mask(vcpu, context);
+	update_permission_bitmask(vcpu, context);
+	update_last_pte_bitmap(vcpu, context);
 
 	ASSERT(is_pae(vcpu));
 	context->new_cr3 = paging_new_cr3;
@@ -3530,6 +3613,8 @@ static int paging32_init_context(struct kvm_vcpu *vcpu,
 	context->root_level = PT32_ROOT_LEVEL;
 
 	reset_rsvds_bits_mask(vcpu, context);
+	update_permission_bitmask(vcpu, context);
+	update_last_pte_bitmap(vcpu, context);
 
 	context->new_cr3 = paging_new_cr3;
 	context->page_fault = paging32_page_fault;
@@ -3590,6 +3675,9 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 		context->gva_to_gpa = paging32_gva_to_gpa;
 	}
 
+	update_permission_bitmask(vcpu, context);
+	update_last_pte_bitmap(vcpu, context);
+
 	return 0;
 }
 
@@ -3665,6 +3753,9 @@ static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
 	}
 
+	update_permission_bitmask(vcpu, g_context);
+	update_last_pte_bitmap(vcpu, g_context);
+
 	return 0;
 }
 

arch/x86/kvm/mmu.h

@@ -18,8 +18,10 @@
 #define PT_PCD_MASK (1ULL << 4)
 #define PT_ACCESSED_SHIFT 5
 #define PT_ACCESSED_MASK (1ULL << PT_ACCESSED_SHIFT)
-#define PT_DIRTY_MASK (1ULL << 6)
-#define PT_PAGE_SIZE_MASK (1ULL << 7)
+#define PT_DIRTY_SHIFT 6
+#define PT_DIRTY_MASK (1ULL << PT_DIRTY_SHIFT)
+#define PT_PAGE_SIZE_SHIFT 7
+#define PT_PAGE_SIZE_MASK (1ULL << PT_PAGE_SIZE_SHIFT)
 #define PT_PAT_MASK (1ULL << 7)
 #define PT_GLOBAL_MASK (1ULL << 8)
 #define PT64_NX_SHIFT 63
@@ -88,17 +90,14 @@ static inline bool is_write_protection(struct kvm_vcpu *vcpu)
 	return kvm_read_cr0_bits(vcpu, X86_CR0_WP);
 }
 
-static inline bool check_write_user_access(struct kvm_vcpu *vcpu,
-					   bool write_fault, bool user_fault,
-					   unsigned long pte)
+/*
+ * Will a fault with a given page-fault error code (pfec) cause a permission
+ * fault with the given access (in ACC_* format)?
+ */
+static inline bool permission_fault(struct kvm_mmu *mmu, unsigned pte_access,
+				    unsigned pfec)
 {
-	if (unlikely(write_fault && !is_writable_pte(pte)
-	      && (user_fault || is_write_protection(vcpu))))
-		return false;
-
-	if (unlikely(user_fault && !(pte & PT_USER_MASK)))
-		return false;
-
-	return true;
+	return (mmu->permissions[pfec >> 1] >> pte_access) & 1;
 }
+
 #endif

arch/x86/kvm/paging_tmpl.h

@@ -63,10 +63,12 @@
  */
 struct guest_walker {
 	int level;
+	unsigned max_level;
 	gfn_t table_gfn[PT_MAX_FULL_LEVELS];
 	pt_element_t ptes[PT_MAX_FULL_LEVELS];
 	pt_element_t prefetch_ptes[PTE_PREFETCH_NUM];
 	gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
+	pt_element_t __user *ptep_user[PT_MAX_FULL_LEVELS];
 	unsigned pt_access;
 	unsigned pte_access;
 	gfn_t gfn;
@@ -101,38 +103,41 @@ static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 	return (ret != orig_pte);
 }
 
-static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte,
-				   bool last)
+static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
+					     struct kvm_mmu *mmu,
+					     struct guest_walker *walker,
+					     int write_fault)
 {
-	unsigned access;
-
-	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
-	if (last && !is_dirty_gpte(gpte))
-		access &= ~ACC_WRITE_MASK;
-
-#if PTTYPE == 64
-	if (vcpu->arch.mmu.nx)
-		access &= ~(gpte >> PT64_NX_SHIFT);
-#endif
-	return access;
-}
-
-static bool FNAME(is_last_gpte)(struct guest_walker *walker,
-				struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
-				pt_element_t gpte)
-{
-	if (walker->level == PT_PAGE_TABLE_LEVEL)
-		return true;
-
-	if ((walker->level == PT_DIRECTORY_LEVEL) && is_large_pte(gpte) &&
-	    (PTTYPE == 64 || is_pse(vcpu)))
-		return true;
+	unsigned level, index;
+	pt_element_t pte, orig_pte;
+	pt_element_t __user *ptep_user;
+	gfn_t table_gfn;
+	int ret;
+
+	for (level = walker->max_level; level >= walker->level; --level) {
+		pte = orig_pte = walker->ptes[level - 1];
+		table_gfn = walker->table_gfn[level - 1];
+		ptep_user = walker->ptep_user[level - 1];
+		index = offset_in_page(ptep_user) / sizeof(pt_element_t);
+		if (!(pte & PT_ACCESSED_MASK)) {
+			trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte));
+			pte |= PT_ACCESSED_MASK;
+		}
+		if (level == walker->level && write_fault && !is_dirty_gpte(pte)) {
+			trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
+			pte |= PT_DIRTY_MASK;
+		}
+		if (pte == orig_pte)
+			continue;
 
-	if ((walker->level == PT_PDPE_LEVEL) && is_large_pte(gpte) &&
-	    (mmu->root_level == PT64_ROOT_LEVEL))
-		return true;
+		ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index, orig_pte, pte);
+		if (ret)
+			return ret;
 
-	return false;
+		mark_page_dirty(vcpu->kvm, table_gfn);
+		walker->ptes[level] = pte;
+	}
+	return 0;
 }
 
 /*
@@ -142,21 +147,22 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
 				    struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 				    gva_t addr, u32 access)
 {
+	int ret;
 	pt_element_t pte;
 	pt_element_t __user *uninitialized_var(ptep_user);
 	gfn_t table_gfn;
-	unsigned index, pt_access, uninitialized_var(pte_access);
+	unsigned index, pt_access, pte_access, accessed_dirty, shift;
 	gpa_t pte_gpa;
-	bool eperm, last_gpte;
 	int offset;
 	const int write_fault = access & PFERR_WRITE_MASK;
 	const int user_fault  = access & PFERR_USER_MASK;
 	const int fetch_fault = access & PFERR_FETCH_MASK;
 	u16 errcode = 0;
+	gpa_t real_gpa;
+	gfn_t gfn;
 
 	trace_kvm_mmu_pagetable_walk(addr, access);
 retry_walk:
-	eperm = false;
 	walker->level = mmu->root_level;
 	pte           = mmu->get_cr3(vcpu);
 
@@ -169,15 +175,21 @@ retry_walk:
 		--walker->level;
 	}
 #endif
+	walker->max_level = walker->level;
 	ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||
 	       (mmu->get_cr3(vcpu) & CR3_NONPAE_RESERVED_BITS) == 0);
 
-	pt_access = ACC_ALL;
+	accessed_dirty = PT_ACCESSED_MASK;
+	pt_access = pte_access = ACC_ALL;
+	++walker->level;
 
-	for (;;) {
+	do {
 		gfn_t real_gfn;
 		unsigned long host_addr;
 
+		pt_access &= pte_access;
+		--walker->level;
+
 		index = PT_INDEX(addr, walker->level);
 
 		table_gfn = gpte_to_gfn(pte);
@@ -199,6 +211,7 @@ retry_walk:
 		ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
 		if (unlikely(__copy_from_user(&pte, ptep_user, sizeof(pte))))
 			goto error;
+		walker->ptep_user[walker->level - 1] = ptep_user;
 
 		trace_kvm_mmu_paging_element(pte, walker->level);
 
@@ -211,92 +224,48 @@ retry_walk:
 			goto error;
 		}
 
-		if (!check_write_user_access(vcpu, write_fault, user_fault,
-					  pte))
-			eperm = true;
-
-#if PTTYPE == 64
-		if (unlikely(fetch_fault && (pte & PT64_NX_MASK)))
-			eperm = true;
-#endif
-
-		last_gpte = FNAME(is_last_gpte)(walker, vcpu, mmu, pte);
-		if (last_gpte) {
-			pte_access = pt_access &
-				     FNAME(gpte_access)(vcpu, pte, true);
-			/* check if the kernel is fetching from user page */
-			if (unlikely(pte_access & PT_USER_MASK) &&
-			    kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
-				if (fetch_fault && !user_fault)
-					eperm = true;
-		}
-
-		if (!eperm && unlikely(!(pte & PT_ACCESSED_MASK))) {
-			int ret;
-			trace_kvm_mmu_set_accessed_bit(table_gfn, index,
-						       sizeof(pte));
-			ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
-						  pte, pte|PT_ACCESSED_MASK);
-			if (unlikely(ret < 0))
-				goto error;
-			else if (ret)
-				goto retry_walk;
-
-			mark_page_dirty(vcpu->kvm, table_gfn);
-			pte |= PT_ACCESSED_MASK;
-		}
+		accessed_dirty &= pte;
+		pte_access = pt_access & gpte_access(vcpu, pte);
 
 		walker->ptes[walker->level - 1] = pte;
+	} while (!is_last_gpte(mmu, walker->level, pte));
 
-		if (last_gpte) {
-			int lvl = walker->level;
-			gpa_t real_gpa;
-			gfn_t gfn;
-			u32 ac;
-
-			gfn = gpte_to_gfn_lvl(pte, lvl);
-			gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT;
-
-			if (PTTYPE == 32 &&
-			    walker->level == PT_DIRECTORY_LEVEL &&
-			    is_cpuid_PSE36())
-				gfn += pse36_gfn_delta(pte);
-
-			ac = write_fault | fetch_fault | user_fault;
+	if (unlikely(permission_fault(mmu, pte_access, access))) {
+		errcode |= PFERR_PRESENT_MASK;
+		goto error;
+	}
 
-			real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn),
-						      ac);
-			if (real_gpa == UNMAPPED_GVA)
-				return 0;
+	gfn = gpte_to_gfn_lvl(pte, walker->level);
+	gfn += (addr & PT_LVL_OFFSET_MASK(walker->level)) >> PAGE_SHIFT;
 
-			walker->gfn = real_gpa >> PAGE_SHIFT;
+	if (PTTYPE == 32 && walker->level == PT_DIRECTORY_LEVEL && is_cpuid_PSE36())
+		gfn += pse36_gfn_delta(pte);
 
-			break;
-		}
+	real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn), access);
+	if (real_gpa == UNMAPPED_GVA)
+		return 0;
 
-		pt_access &= FNAME(gpte_access)(vcpu, pte, false);
-		--walker->level;
-	}
+	walker->gfn = real_gpa >> PAGE_SHIFT;
 
-	if (unlikely(eperm)) {
-		errcode |= PFERR_PRESENT_MASK;
-		goto error;
-	}
+	if (!write_fault)
+		protect_clean_gpte(&pte_access, pte);
 
-	if (write_fault && unlikely(!is_dirty_gpte(pte))) {
-		int ret;
+	/*
+	 * On a write fault, fold the dirty bit into accessed_dirty by shifting it one
+	 * place right.
+	 *
+	 * On a read fault, do nothing.
+	 */
+	shift = write_fault >> ilog2(PFERR_WRITE_MASK);
+	shift *= PT_DIRTY_SHIFT - PT_ACCESSED_SHIFT;
+	accessed_dirty &= pte >> shift;
 
-		trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
-		ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index,
-					  pte, pte|PT_DIRTY_MASK);
+	if (unlikely(!accessed_dirty)) {
+		ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker, write_fault);
 		if (unlikely(ret < 0))
 			goto error;
 		else if (ret)
 			goto retry_walk;
-
-		mark_page_dirty(vcpu->kvm, table_gfn);
-		pte |= PT_DIRTY_MASK;
-		walker->ptes[walker->level - 1] = pte;
 	}
 
 	walker->pt_access = pt_access;
@@ -368,7 +337,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 		return;
 
 	pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
-	pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte, true);
+	pte_access = sp->role.access & gpte_access(vcpu, gpte);
+	protect_clean_gpte(&pte_access, gpte);
 	pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
 	if (mmu_invalid_pfn(pfn))
 		return;
@@ -441,8 +411,8 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
 		if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
 			continue;
 
-		pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte,
-								  true);
+		pte_access = sp->role.access & gpte_access(vcpu, gpte);
+		protect_clean_gpte(&pte_access, gpte);
 		gfn = gpte_to_gfn(gpte);
 		pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
 				      pte_access & ACC_WRITE_MASK);
@@ -794,7 +764,8 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 
 		gfn = gpte_to_gfn(gpte);
 		pte_access = sp->role.access;
-		pte_access &= FNAME(gpte_access)(vcpu, gpte, true);
+		pte_access &= gpte_access(vcpu, gpte);
+		protect_clean_gpte(&pte_access, gpte);
 
 		if (sync_mmio_spte(&sp->spt[i], gfn, pte_access, &nr_present))
 			continue;

arch/x86/kvm/svm.c

@@ -3782,12 +3782,6 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
 	svm_complete_interrupts(svm);
 }
 
-#ifdef CONFIG_X86_64
-#define R "r"
-#else
-#define R "e"
-#endif
-
 static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -3814,13 +3808,13 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	local_irq_enable();
 
 	asm volatile (
-		"push %%"R"bp; \n\t"
-		"mov %c[rbx](%[svm]), %%"R"bx \n\t"
-		"mov %c[rcx](%[svm]), %%"R"cx \n\t"
-		"mov %c[rdx](%[svm]), %%"R"dx \n\t"
-		"mov %c[rsi](%[svm]), %%"R"si \n\t"
-		"mov %c[rdi](%[svm]), %%"R"di \n\t"
-		"mov %c[rbp](%[svm]), %%"R"bp \n\t"
+		"push %%" _ASM_BP "; \n\t"
+		"mov %c[rbx](%[svm]), %%" _ASM_BX " \n\t"
+		"mov %c[rcx](%[svm]), %%" _ASM_CX " \n\t"
+		"mov %c[rdx](%[svm]), %%" _ASM_DX " \n\t"
+		"mov %c[rsi](%[svm]), %%" _ASM_SI " \n\t"
+		"mov %c[rdi](%[svm]), %%" _ASM_DI " \n\t"
+		"mov %c[rbp](%[svm]), %%" _ASM_BP " \n\t"
 #ifdef CONFIG_X86_64
 		"mov %c[r8](%[svm]),  %%r8  \n\t"
 		"mov %c[r9](%[svm]),  %%r9  \n\t"
@@ -3833,20 +3827,20 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 #endif
 
 		/* Enter guest mode */
-		"push %%"R"ax \n\t"
-		"mov %c[vmcb](%[svm]), %%"R"ax \n\t"
+		"push %%" _ASM_AX " \n\t"
+		"mov %c[vmcb](%[svm]), %%" _ASM_AX " \n\t"
 		__ex(SVM_VMLOAD) "\n\t"
 		__ex(SVM_VMRUN) "\n\t"
 		__ex(SVM_VMSAVE) "\n\t"
-		"pop %%"R"ax \n\t"
+		"pop %%" _ASM_AX " \n\t"
 
 		/* Save guest registers, load host registers */
-		"mov %%"R"bx, %c[rbx](%[svm]) \n\t"
-		"mov %%"R"cx, %c[rcx](%[svm]) \n\t"
-		"mov %%"R"dx, %c[rdx](%[svm]) \n\t"
-		"mov %%"R"si, %c[rsi](%[svm]) \n\t"
-		"mov %%"R"di, %c[rdi](%[svm]) \n\t"
-		"mov %%"R"bp, %c[rbp](%[svm]) \n\t"
+		"mov %%" _ASM_BX ", %c[rbx](%[svm]) \n\t"
+		"mov %%" _ASM_CX ", %c[rcx](%[svm]) \n\t"
+		"mov %%" _ASM_DX ", %c[rdx](%[svm]) \n\t"
+		"mov %%" _ASM_SI ", %c[rsi](%[svm]) \n\t"
+		"mov %%" _ASM_DI ", %c[rdi](%[svm]) \n\t"
+		"mov %%" _ASM_BP ", %c[rbp](%[svm]) \n\t"
 #ifdef CONFIG_X86_64
 		"mov %%r8,  %c[r8](%[svm]) \n\t"
 		"mov %%r9,  %c[r9](%[svm]) \n\t"
@@ -3857,7 +3851,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 		"mov %%r14, %c[r14](%[svm]) \n\t"
 		"mov %%r15, %c[r15](%[svm]) \n\t"
 #endif
-		"pop %%"R"bp"
+		"pop %%" _ASM_BP
 		:
 		: [svm]"a"(svm),
 		  [vmcb]"i"(offsetof(struct vcpu_svm, vmcb_pa)),
@@ -3878,9 +3872,11 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 		  [r15]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R15]))
 #endif
 		: "cc", "memory"
-		, R"bx", R"cx", R"dx", R"si", R"di"
 #ifdef CONFIG_X86_64
+		, "rbx", "rcx", "rdx", "rsi", "rdi"
 		, "r8", "r9", "r10", "r11" , "r12", "r13", "r14", "r15"
+#else
+		, "ebx", "ecx", "edx", "esi", "edi"
 #endif
 		);
 
@@ -3940,8 +3936,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	mark_all_clean(svm->vmcb);
 }
 
-#undef R
-
 static void svm_set_cr3(struct kvm_vcpu *vcpu, unsigned long root)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);

arch/x86/kvm/vmx.c

@@ -127,6 +127,8 @@ module_param(ple_gap, int, S_IRUGO);
 static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW;
 module_param(ple_window, int, S_IRUGO);
 
+extern const ulong vmx_return;
+
 #define NR_AUTOLOAD_MSRS 8
 #define VMCS02_POOL_SIZE 1
 
@@ -3724,8 +3726,7 @@ static void vmx_set_constant_host_state(void)
 	native_store_idt(&dt);
 	vmcs_writel(HOST_IDTR_BASE, dt.address);   /* 22.2.4 */
 
-	asm("mov $.Lkvm_vmx_return, %0" : "=r"(tmpl));
-	vmcs_writel(HOST_RIP, tmpl); /* 22.2.5 */
+	vmcs_writel(HOST_RIP, vmx_return); /* 22.2.5 */
 
 	rdmsr(MSR_IA32_SYSENTER_CS, low32, high32);
 	vmcs_write32(HOST_IA32_SYSENTER_CS, low32);
@@ -6183,14 +6184,6 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx)
 					msrs[i].host);
 }
 
-#ifdef CONFIG_X86_64
-#define R "r"
-#define Q "q"
-#else
-#define R "e"
-#define Q "l"
-#endif
-
 static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -6239,30 +6232,30 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	vmx->__launched = vmx->loaded_vmcs->launched;
 	asm(
 		/* Store host registers */
-		"push %%"R"dx; push %%"R"bp;"
-		"push %%"R"cx \n\t" /* placeholder for guest rcx */
-		"push %%"R"cx \n\t"
-		"cmp %%"R"sp, %c[host_rsp](%0) \n\t"
+		"push %%" _ASM_DX "; push %%" _ASM_BP ";"
+		"push %%" _ASM_CX " \n\t" /* placeholder for guest rcx */
+		"push %%" _ASM_CX " \n\t"
+		"cmp %%" _ASM_SP ", %c[host_rsp](%0) \n\t"
 		"je 1f \n\t"
-		"mov %%"R"sp, %c[host_rsp](%0) \n\t"
+		"mov %%" _ASM_SP ", %c[host_rsp](%0) \n\t"
 		__ex(ASM_VMX_VMWRITE_RSP_RDX) "\n\t"
 		"1: \n\t"
 		/* Reload cr2 if changed */
-		"mov %c[cr2](%0), %%"R"ax \n\t"
-		"mov %%cr2, %%"R"dx \n\t"
-		"cmp %%"R"ax, %%"R"dx \n\t"
+		"mov %c[cr2](%0), %%" _ASM_AX " \n\t"
+		"mov %%cr2, %%" _ASM_DX " \n\t"
+		"cmp %%" _ASM_AX ", %%" _ASM_DX " \n\t"
 		"je 2f \n\t"
-		"mov %%"R"ax, %%cr2 \n\t"
+		"mov %%" _ASM_AX", %%cr2 \n\t"
 		"2: \n\t"
 		/* Check if vmlaunch of vmresume is needed */
 		"cmpl $0, %c[launched](%0) \n\t"
 		/* Load guest registers.  Don't clobber flags. */
-		"mov %c[rax](%0), %%"R"ax \n\t"
-		"mov %c[rbx](%0), %%"R"bx \n\t"
-		"mov %c[rdx](%0), %%"R"dx \n\t"
-		"mov %c[rsi](%0), %%"R"si \n\t"
-		"mov %c[rdi](%0), %%"R"di \n\t"
-		"mov %c[rbp](%0), %%"R"bp \n\t"
+		"mov %c[rax](%0), %%" _ASM_AX " \n\t"
+		"mov %c[rbx](%0), %%" _ASM_BX " \n\t"
+		"mov %c[rdx](%0), %%" _ASM_DX " \n\t"
+		"mov %c[rsi](%0), %%" _ASM_SI " \n\t"
+		"mov %c[rdi](%0), %%" _ASM_DI " \n\t"
+		"mov %c[rbp](%0), %%" _ASM_BP " \n\t"
 #ifdef CONFIG_X86_64
 		"mov %c[r8](%0),  %%r8  \n\t"
 		"mov %c[r9](%0),  %%r9  \n\t"
@@ -6273,24 +6266,24 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 		"mov %c[r14](%0), %%r14 \n\t"
 		"mov %c[r15](%0), %%r15 \n\t"
 #endif
-		"mov %c[rcx](%0), %%"R"cx \n\t" /* kills %0 (ecx) */
+		"mov %c[rcx](%0), %%" _ASM_CX " \n\t" /* kills %0 (ecx) */
 
 		/* Enter guest mode */
-		"jne .Llaunched \n\t"
+		"jne 1f \n\t"
 		__ex(ASM_VMX_VMLAUNCH) "\n\t"
-		"jmp .Lkvm_vmx_return \n\t"
-		".Llaunched: " __ex(ASM_VMX_VMRESUME) "\n\t"
-		".Lkvm_vmx_return: "
+		"jmp 2f \n\t"
+		"1: " __ex(ASM_VMX_VMRESUME) "\n\t"
+		"2: "
 		/* Save guest registers, load host registers, keep flags */
-		"mov %0, %c[wordsize](%%"R"sp) \n\t"
+		"mov %0, %c[wordsize](%%" _ASM_SP ") \n\t"
 		"pop %0 \n\t"
-		"mov %%"R"ax, %c[rax](%0) \n\t"
-		"mov %%"R"bx, %c[rbx](%0) \n\t"
-		"pop"Q" %c[rcx](%0) \n\t"
-		"mov %%"R"dx, %c[rdx](%0) \n\t"
-		"mov %%"R"si, %c[rsi](%0) \n\t"
-		"mov %%"R"di, %c[rdi](%0) \n\t"
-		"mov %%"R"bp, %c[rbp](%0) \n\t"
+		"mov %%" _ASM_AX ", %c[rax](%0) \n\t"
+		"mov %%" _ASM_BX ", %c[rbx](%0) \n\t"
+		__ASM_SIZE(pop) " %c[rcx](%0) \n\t"
+		"mov %%" _ASM_DX ", %c[rdx](%0) \n\t"
+		"mov %%" _ASM_SI ", %c[rsi](%0) \n\t"
+		"mov %%" _ASM_DI ", %c[rdi](%0) \n\t"
+		"mov %%" _ASM_BP ", %c[rbp](%0) \n\t"
 #ifdef CONFIG_X86_64
 		"mov %%r8,  %c[r8](%0) \n\t"
 		"mov %%r9,  %c[r9](%0) \n\t"
@@ -6301,11 +6294,15 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 		"mov %%r14, %c[r14](%0) \n\t"
 		"mov %%r15, %c[r15](%0) \n\t"
 #endif
-		"mov %%cr2, %%"R"ax   \n\t"
-		"mov %%"R"ax, %c[cr2](%0) \n\t"
+		"mov %%cr2, %%" _ASM_AX "   \n\t"
+		"mov %%" _ASM_AX ", %c[cr2](%0) \n\t"
 
-		"pop  %%"R"bp; pop  %%"R"dx \n\t"
+		"pop  %%" _ASM_BP "; pop  %%" _ASM_DX " \n\t"
 		"setbe %c[fail](%0) \n\t"
+		".pushsection .rodata \n\t"
+		".global vmx_return \n\t"
+		"vmx_return: " _ASM_PTR " 2b \n\t"
+		".popsection"
 	      : : "c"(vmx), "d"((unsigned long)HOST_RSP),
 		[launched]"i"(offsetof(struct vcpu_vmx, __launched)),
 		[fail]"i"(offsetof(struct vcpu_vmx, fail)),
@@ -6330,9 +6327,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 		[cr2]"i"(offsetof(struct vcpu_vmx, vcpu.arch.cr2)),
 		[wordsize]"i"(sizeof(ulong))
 	      : "cc", "memory"
-		, R"ax", R"bx", R"di", R"si"
 #ifdef CONFIG_X86_64
+		, "rax", "rbx", "rdi", "rsi"
 		, "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
+#else
+		, "eax", "ebx", "edi", "esi"
 #endif
 	      );
 
@@ -6384,9 +6383,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	vmx_complete_interrupts(vmx);
 }
 
-#undef R
-#undef Q
-
 static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);

arch/x86/kvm/x86.c

@@ -3672,20 +3672,17 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
 				gpa_t *gpa, struct x86_exception *exception,
 				bool write)
 {
-	u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
+	u32 access = ((kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0)
+		| (write ? PFERR_WRITE_MASK : 0);
 
-	if (vcpu_match_mmio_gva(vcpu, gva) &&
-		  check_write_user_access(vcpu, write, access,
-		  vcpu->arch.access)) {
+	if (vcpu_match_mmio_gva(vcpu, gva)
+	    && !permission_fault(vcpu->arch.walk_mmu, vcpu->arch.access, access)) {
 		*gpa = vcpu->arch.mmio_gfn << PAGE_SHIFT |
 					(gva & (PAGE_SIZE - 1));
 		trace_vcpu_match_mmio(gva, *gpa, write, false);
 		return 1;
 	}
 
-	if (write)
-		access |= PFERR_WRITE_MASK;
-
 	*gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
 
 	if (*gpa == UNMAPPED_GVA)
@@ -6016,7 +6013,9 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 	int r;
 
 	vcpu->arch.mtrr_state.have_fixed = 1;
-	vcpu_load(vcpu);
+	r = vcpu_load(vcpu);
+	if (r)
+		return r;
 	r = kvm_arch_vcpu_reset(vcpu);
 	if (r == 0)
 		r = kvm_mmu_setup(vcpu);
@@ -6027,9 +6026,11 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
+	int r;
 	vcpu->arch.apf.msr_val = 0;
 
-	vcpu_load(vcpu);
+	r = vcpu_load(vcpu);
+	BUG_ON(r);
 	kvm_mmu_unload(vcpu);
 	vcpu_put(vcpu);
 
@@ -6275,7 +6276,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
 {
-	vcpu_load(vcpu);
+	int r;
+	r = vcpu_load(vcpu);
+	BUG_ON(r);
 	kvm_mmu_unload(vcpu);
 	vcpu_put(vcpu);
 }

include/linux/kvm_host.h

@@ -408,7 +408,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id);
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu);
 
-void vcpu_load(struct kvm_vcpu *vcpu);
+int __must_check vcpu_load(struct kvm_vcpu *vcpu);
 void vcpu_put(struct kvm_vcpu *vcpu);
 
 int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,

virt/kvm/kvm_main.c

@@ -131,11 +131,12 @@ bool kvm_is_mmio_pfn(pfn_t pfn)
 /*
  * Switches to specified vcpu, until a matching vcpu_put()
  */
-void vcpu_load(struct kvm_vcpu *vcpu)
+int vcpu_load(struct kvm_vcpu *vcpu)
 {
 	int cpu;
 
-	mutex_lock(&vcpu->mutex);
+	if (mutex_lock_killable(&vcpu->mutex))
+		return -EINTR;
 	if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) {
 		/* The thread running this VCPU changed. */
 		struct pid *oldpid = vcpu->pid;
@@ -148,6 +149,7 @@ void vcpu_load(struct kvm_vcpu *vcpu)
 	preempt_notifier_register(&vcpu->preempt_notifier);
 	kvm_arch_vcpu_load(vcpu, cpu);
 	put_cpu();
+	return 0;
 }
 
 void vcpu_put(struct kvm_vcpu *vcpu)
@@ -1891,7 +1893,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 #endif
 
 
-	vcpu_load(vcpu);
+	r = vcpu_load(vcpu);
+	if (r)
+		return r;
 	switch (ioctl) {
 	case KVM_RUN:
 		r = -EINVAL;