vcpu: add get/set register APIs

there will be 3 types of vcpu runtime contexts:
- runtime contexts always saved/restored during VM exit/entry, which
  include general registers rax/rcx/rdx/rbx/rbp/rsi/rdi/r8~r15, cr2 and
  msr for spectre control (ia32_spec_ctrl)
- runtime contexts on-demand cached/updated during VM exit/entry, which
  include frequently used registers rsp, rip, efer, rflags, cr0 and cr4
- runtime contexts always read/write from/to VMCS, which include left
  registers not in above

this patch add get/set register APIs for vcpu runtime contexts, and unified
the save/restore method for them according to above description.

v3:
- update vcpu_get/set_cr0/4 as unified interface to get/set guest cr0/cr4,
  use on-demand cache for reading, but always write to VMCS for writing.

v2:
- use reg_cached/reg_updated for on-demand runtime contexts
- always read/write cr3 from/to VMCS

Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/include/arch/x86/cpu.h

@@ -152,6 +152,65 @@
 
 #ifndef ASSEMBLER
 
+/**
+ *
+ * Identifiers for architecturally defined registers.
+ *
+ * These register names is used in condition statement.
+ * Within the following groups,register name need to be
+ * kept in order:
+ * General register names group (CPU_REG_RAX~CPU_REG_R15);
+ * Non general register names group (CPU_REG_CR0~CPU_REG_GDTR);
+ * Segement register names group (CPU_REG_ES~CPU_REG_GS).
+ */
+enum cpu_reg_name {
+	/* General purpose register layout should align with
+	 * struct cpu_gp_regs
+	 */
+	CPU_REG_RAX,
+	CPU_REG_RCX,
+	CPU_REG_RDX,
+	CPU_REG_RBX,
+	CPU_REG_RSP,
+	CPU_REG_RBP,
+	CPU_REG_RSI,
+	CPU_REG_RDI,
+	CPU_REG_R8,
+	CPU_REG_R9,
+	CPU_REG_R10,
+	CPU_REG_R11,
+	CPU_REG_R12,
+	CPU_REG_R13,
+	CPU_REG_R14,
+	CPU_REG_R15,
+
+	CPU_REG_CR0,
+	CPU_REG_CR2,
+	CPU_REG_CR3,
+	CPU_REG_CR4,
+	CPU_REG_DR7,
+	CPU_REG_RIP,
+	CPU_REG_RFLAGS,
+	/*CPU_REG_NATURAL_LAST*/
+	CPU_REG_EFER,
+	CPU_REG_PDPTE0,
+	CPU_REG_PDPTE1,
+	CPU_REG_PDPTE2,
+	CPU_REG_PDPTE3,
+	/*CPU_REG_64BIT_LAST,*/
+	CPU_REG_ES,
+	CPU_REG_CS,
+	CPU_REG_SS,
+	CPU_REG_DS,
+	CPU_REG_FS,
+	CPU_REG_GS,
+	CPU_REG_LDTR,
+	CPU_REG_TR,
+	CPU_REG_IDTR,
+	CPU_REG_GDTR
+	/*CPU_REG_LAST*/
+};
+
 /**********************************/
 /* EXTERNAL VARIABLES             */
 /**********************************/

hypervisor/include/arch/x86/guest/vcpu.h

@@ -263,6 +263,8 @@ struct vcpu {
 #ifdef CONFIG_MTRR_ENABLED
 	struct mtrr_state mtrr;
 #endif
+	uint64_t reg_cached;
+	uint64_t reg_updated;
 };
 
 #define	is_vcpu_bsp(vcpu)	((vcpu)->vcpu_id == BOOT_CPU_ID)
@@ -273,6 +275,25 @@ static inline void vcpu_retain_rip(struct vcpu *vcpu)
 }
 
 /* External Interfaces */
+uint64_t vcpu_get_gpreg(struct vcpu *vcpu, uint32_t reg);
+void vcpu_set_gpreg(struct vcpu *vcpu, uint32_t reg, uint64_t val);
+uint64_t vcpu_get_rip(struct vcpu *vcpu);
+void vcpu_set_rip(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_rsp(struct vcpu *vcpu);
+void vcpu_set_rsp(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_efer(struct vcpu *vcpu);
+void vcpu_set_efer(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_rflags(struct vcpu *vcpu);
+void vcpu_set_rflags(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_cr0(struct vcpu *vcpu);
+int vcpu_set_cr0(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_cr2(struct vcpu *vcpu);
+void vcpu_set_cr2(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_cr4(struct vcpu *vcpu);
+int vcpu_set_cr4(struct vcpu *vcpu, uint64_t val);
+uint64_t vcpu_get_pat_ext(struct vcpu *vcpu);
+void vcpu_set_pat_ext(struct vcpu *vcpu, uint64_t val);
+
 struct vcpu* get_ever_run_vcpu(uint16_t pcpu_id);
 int create_vcpu(uint16_t pcpu_id, struct vm *vm, struct vcpu **rtn_vcpu_handle);
 int start_vcpu(struct vcpu *vcpu);

hypervisor/include/arch/x86/vmx.h

@@ -447,7 +447,6 @@ uint64_t vmx_rdmsr_pat(struct vcpu *vcpu);
 int vmx_wrmsr_pat(struct vcpu *vcpu, uint64_t value);
 
 int vmx_write_cr0(struct vcpu *vcpu, uint64_t cr0);
-int vmx_write_cr3(struct vcpu *vcpu, uint64_t cr3);
 int vmx_write_cr4(struct vcpu *vcpu, uint64_t cr4);
 
 static inline enum vm_cpu_mode get_vcpu_mode(struct vcpu *vcpu)