diff mbox

[2/7] Nested VMX patch 2 implements vmclear

Message ID 1260470309-7166-3-git-send-email-oritw@il.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

oritw@il.ibm.com Dec. 10, 2009, 6:38 p.m. UTC
None
diff mbox

Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2726a6c..a7ffd5e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -93,13 +93,39 @@  struct shared_msr_entry {
 };
 
 struct __attribute__ ((__packed__)) level_state {
+	/* Has the level1 guest done vmclear? */
+	bool vmclear;
+};
+
+/*
+ * This structure is mapped to guest memory.
+ * It is packed in order to preseve the binary content
+ * after live migration.
+ * If there are changed in the content or layout the revision_id must be updated.
+ */
+struct __attribute__ ((__packed__)) nested_vmcs_page {
+	u32 revision_id;
+	u32 abort;
+	struct level_state l2_state;
+};
+
+struct nested_vmcs_list {
+	struct list_head list;
+	gpa_t vmcs_addr;
+	struct vmcs *l2_vmcs;
 };
 
 struct nested_vmx {
 	/* Has the level1 guest done vmxon? */
 	bool vmxon;
+	/* What is the location of the current vmcs l1 keeps for l2 */
+	gpa_t current_vmptr;
 	/* Level 1 state for switching to level 2 and back */
 	struct level_state *l1_state;
+	/* list of vmcs for each l2 guest created by l1 */
+	struct list_head l2_vmcs_list;
+	/* l2 page corresponding to the current vmcs set by l1 */
+	struct nested_vmcs_page *current_l2_page;
 };
 
 struct vcpu_vmx {
@@ -156,6 +182,76 @@  static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
 	return container_of(vcpu, struct vcpu_vmx, vcpu);
 }
 
+static struct page *nested_get_page(struct kvm_vcpu *vcpu,
+				    u64 vmcs_addr)
+{
+	struct page *vmcs_page = NULL;
+
+	down_read(&current->mm->mmap_sem);
+	vmcs_page = gfn_to_page(vcpu->kvm, vmcs_addr >> PAGE_SHIFT);
+	up_read(&current->mm->mmap_sem);
+
+	if (is_error_page(vmcs_page)) {
+		printk(KERN_ERR "%s error allocating page 0x%llx\n",
+		       __func__, vmcs_addr);
+		kvm_release_page_clean(vmcs_page);
+		return NULL;
+	}
+
+	return vmcs_page;
+
+}
+
+static int nested_map_current(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct page *vmcs_page =
+		nested_get_page(vcpu, vmx->nested.current_vmptr);
+	struct nested_vmcs_page *mapped_page;
+
+	if (vmcs_page == NULL) {
+		printk(KERN_INFO "%s: failure in nested_get_page\n", __func__);
+		return 0;
+	}
+
+	if (vmx->nested.current_l2_page) {
+		printk(KERN_INFO "%s: shadow vmcs already mapped\n", __func__);
+		WARN_ON(1);
+		return 0;
+	}
+
+	mapped_page = kmap_atomic(vmcs_page, KM_USER0);
+
+	if (!mapped_page) {
+		printk(KERN_INFO "%s: error in kmap_atomic\n", __func__);
+		return 0;
+	}
+
+	vmx->nested.current_l2_page = mapped_page;
+
+	return 1;
+}
+
+static void nested_unmap_current(struct kvm_vcpu *vcpu)
+{
+	struct page *page;
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+	if (!vmx->nested.current_l2_page) {
+		printk(KERN_INFO "Shadow vmcs already unmapped\n");
+		WARN_ON(1);
+		return;
+	}
+
+	page = kmap_atomic_to_page(vmx->nested.current_l2_page);
+
+	kunmap_atomic(vmx->nested.current_l2_page, KM_USER0);
+
+	kvm_release_page_dirty(page);
+
+	vmx->nested.current_l2_page = NULL;
+}
+
 static int init_rmode(struct kvm *kvm);
 static u64 construct_eptp(unsigned long root_hpa);
 
@@ -1144,6 +1240,35 @@  static int nested_vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
 	return 0;
 }
 
+static int read_guest_vmcs_gpa(struct kvm_vcpu *vcpu, gva_t gva, u64 *gentry)
+{
+	int r = 0;
+	uint size;
+
+	*gentry = 0;
+
+	if (is_long_mode(vcpu))
+		size = sizeof(u64);
+	else
+		size = sizeof(u32);
+
+	r = kvm_read_guest_virt(gva, gentry,
+				size, vcpu);
+	if (r) {
+		printk(KERN_ERR "%s cannot read guest vmcs addr %lx : %d\n",
+		       __func__, vcpu->arch.regs[VCPU_REGS_RAX], r);
+		return r;
+	}
+
+	if (!IS_ALIGNED(*gentry, PAGE_SIZE)) {
+		printk(KERN_DEBUG "%s addr %llx not aligned\n",
+		       __func__, *gentry);
+		return 1;
+	}
+
+	return 0;
+}
+
 /*
  * Writes msr value into into the appropriate "register".
  * Returns 0 on success, non-0 otherwise.
@@ -1316,6 +1441,7 @@  static int create_l1_state(struct kvm_vcpu *vcpu)
 	} else
 		return 0;
 
+	INIT_LIST_HEAD(&(vmx->nested.l2_vmcs_list));
 	return 0;
 }
 
@@ -1488,15 +1614,35 @@  static void free_vmcs(struct vmcs *vmcs)
 	free_pages((unsigned long)vmcs, vmcs_config.order);
 }
 
+static void nested_free_current_vmcs(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct nested_vmcs_list *list_item, *n;
+
+	list_for_each_entry_safe(list_item, n, &vmx->nested.l2_vmcs_list, list)
+		if (list_item->vmcs_addr == vmx->nested.current_vmptr) {
+			free_vmcs(list_item->l2_vmcs);
+			list_del(&(list_item->list));
+			return;
+		}
+}
+
 static void free_l1_state(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct nested_vmcs_list *list_item, *n;
 
 	if (!vmx->nested.l1_state)
 		return;
 
 	kfree(vmx->nested.l1_state);
 	vmx->nested.l1_state = NULL;
+
+	list_for_each_entry_safe(list_item, n, &vmx->nested.l2_vmcs_list,
+				 list) {
+		free_vmcs(list_item->l2_vmcs);
+		list_del(&(list_item->list));
+	}
 }
 
 
@@ -3352,6 +3498,93 @@  static int handle_vmx_insn(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static void clear_rflags_cf_zf(struct kvm_vcpu *vcpu)
+{
+	unsigned long rflags;
+	rflags = vmx_get_rflags(vcpu);
+	rflags &= ~(X86_EFLAGS_CF | X86_EFLAGS_ZF);
+	vmx_set_rflags(vcpu, rflags);
+}
+
+/*
+ * Decode the memory address (operand) of a vmx instruction according to Table 23-12/23-11
+ * For additional information regarding offset calculation see 3.7.5
+ */
+static gva_t get_vmx_mem_address(struct kvm_vcpu *vcpu,
+				 unsigned long exit_qualification,
+				 u32 vmx_instruction_info)
+{
+	int  scaling        = vmx_instruction_info & 3;             /* bits 0:1 scaling */
+	int  addr_size      = (vmx_instruction_info >> 7) & 7;      /* bits 7:9 address size, 0=16bit, 1=32bit, 2=64bit */
+	bool is_reg         = vmx_instruction_info & (1u << 10);    /* bit  10  1=register operand, 0= memory */
+	int  seg_reg        = (vmx_instruction_info >> 15) & 7;     /* bits 15:17 segment register */
+	int  index_reg      = (vmx_instruction_info >> 18) & 0xf;   /* bits 18:21 index register */
+	bool index_is_valid = !(vmx_instruction_info & (1u << 22)); /* bit  22 index register validity, 0=valid, 1=invalid */
+	int  base_reg       = (vmx_instruction_info >> 23) & 0xf;   /* bits 23:26 index register */
+	bool base_is_valid  = !(vmx_instruction_info & (1u << 27)); /* bit  27 base register validity, 0=valid, 1=invalid */
+	gva_t addr;
+
+	if (is_reg)
+		return 0;
+
+	switch (addr_size) {
+	case 1:
+		exit_qualification &= 0xffffffff; /* 32 high bits are undefied according to the spec, page 23-7 */
+		break;
+	case 2:
+		break;
+	default:
+		return 0;
+	}
+
+	/* Addr = segment_base + offset */
+	/* offfset = Base + [Index * Scale] + Displacement, see Figure 3-11 */
+	addr = vmx_get_segment_base(vcpu, seg_reg);
+	if (base_is_valid)
+		addr += kvm_register_read(vcpu, base_reg);
+	if (index_is_valid)
+		addr += kvm_register_read(vcpu, index_reg)*scaling;
+	addr += exit_qualification; /* exit qualification holds the displacement, spec page 23-7 */
+
+	return addr;
+}
+
+static int handle_vmclear(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct level_state *l2_state;
+	gpa_t guest_vmcs_addr;
+	unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
+	u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+	gva_t vmcs_gva;
+
+	if (!nested_vmx_check_permission(vcpu))
+		return 1;
+
+	vmcs_gva = get_vmx_mem_address(vcpu, exit_qualification,
+				       vmx_instruction_info);
+
+	if (read_guest_vmcs_gpa(vcpu, vmcs_gva, &guest_vmcs_addr))
+		return 1;
+
+	vmx->nested.current_vmptr = guest_vmcs_addr;
+	if (!nested_map_current(vcpu))
+		return 1;
+
+	l2_state = &(to_vmx(vcpu)->nested.current_l2_page->l2_state);
+	l2_state->vmclear = 1;
+	nested_free_current_vmcs(vcpu);
+
+	vmx->nested.current_vmptr = -1ull;
+
+	nested_unmap_current(vcpu);
+
+	skip_emulated_instruction(vcpu);
+	clear_rflags_cf_zf(vcpu);
+
+	return 1;
+}
+
 static int handle_vmoff(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -3695,7 +3928,7 @@  static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 	[EXIT_REASON_HLT]                     = handle_halt,
 	[EXIT_REASON_INVLPG]		      = handle_invlpg,
 	[EXIT_REASON_VMCALL]                  = handle_vmcall,
-	[EXIT_REASON_VMCLEAR]	              = handle_vmx_insn,
+	[EXIT_REASON_VMCLEAR]	              = handle_vmclear,
 	[EXIT_REASON_VMLAUNCH]                = handle_vmx_insn,
 	[EXIT_REASON_VMPTRLD]                 = handle_vmx_insn,
 	[EXIT_REASON_VMPTRST]                 = handle_vmx_insn,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b698952..e5acf22 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2773,8 +2773,8 @@  static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
 	return kvm_io_bus_read(&vcpu->kvm->mmio_bus, addr, len, v);
 }
 
-static int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
-			       struct kvm_vcpu *vcpu)
+int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
+			struct kvm_vcpu *vcpu)
 {
 	void *data = val;
 	int r = X86EMUL_CONTINUE;
@@ -2802,6 +2802,7 @@  static int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
 out:
 	return r;
 }
+EXPORT_SYMBOL_GPL(kvm_read_guest_virt);
 
 static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
 				struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 57204cb..2d7b2dc 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -35,6 +35,9 @@  static inline bool kvm_exception_is_soft(unsigned int nr)
 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
                                              u32 function, u32 index);
 
+int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
+			struct kvm_vcpu *vcpu);
+
 extern int nested;
 
 #endif