# Commit f54b63e8617ada823be43d60467a43c8224b7909
# Date 2018-07-04 12:12:14 +0100
# Author Andrew Cooper <andrew.cooper3@citrix.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
x86/vmx: API improvements for MSR load/save infrastructure

Collect together related infrastructure in vmcs.h, rather than having it
spread out.  Turn vmx_{read,write}_guest_msr() into static inlines, as they
are simple enough.

Replace 'int type' with 'enum vmx_msr_list_type', and use switch statements
internally.  Later changes are going to introduce a new type.

Rename the type identifiers for consistency with the other VMX_MSR_*
constants.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1296,22 +1296,26 @@ static int vmx_msr_entry_key_cmp(const v
     return 0;
 }
 
-struct vmx_msr_entry *vmx_find_msr(u32 msr, int type)
+struct vmx_msr_entry *vmx_find_msr(uint32_t msr, enum vmx_msr_list_type type)
 {
     struct vcpu *curr = current;
     unsigned int msr_count;
-    struct vmx_msr_entry *msr_area;
+    struct vmx_msr_entry *msr_area = NULL;
 
-    if ( type == VMX_GUEST_MSR )
+    switch ( type )
     {
-        msr_count = curr->arch.hvm_vmx.msr_count;
-        msr_area = curr->arch.hvm_vmx.msr_area;
-    }
-    else
-    {
-        ASSERT(type == VMX_HOST_MSR);
+    case VMX_MSR_HOST:
         msr_count = curr->arch.hvm_vmx.host_msr_count;
         msr_area = curr->arch.hvm_vmx.host_msr_area;
+        break;
+
+    case VMX_MSR_GUEST:
+        msr_count = curr->arch.hvm_vmx.msr_count;
+        msr_area = curr->arch.hvm_vmx.msr_area;
+        break;
+
+    default:
+        ASSERT_UNREACHABLE();
     }
 
     if ( msr_area == NULL )
@@ -1321,48 +1325,27 @@ struct vmx_msr_entry *vmx_find_msr(u32 m
                    vmx_msr_entry_key_cmp);
 }
 
-int vmx_read_guest_msr(u32 msr, u64 *val)
-{
-    struct vmx_msr_entry *ent;
-
-    if ( (ent = vmx_find_msr(msr, VMX_GUEST_MSR)) != NULL )
-    {
-        *val = ent->data;
-        return 0;
-    }
-
-    return -ESRCH;
-}
-
-int vmx_write_guest_msr(u32 msr, u64 val)
-{
-    struct vmx_msr_entry *ent;
-
-    if ( (ent = vmx_find_msr(msr, VMX_GUEST_MSR)) != NULL )
-    {
-        ent->data = val;
-        return 0;
-    }
-
-    return -ESRCH;
-}
-
-int vmx_add_msr(u32 msr, int type)
+int vmx_add_msr(uint32_t msr, enum vmx_msr_list_type type)
 {
     struct vcpu *curr = current;
     unsigned int idx, *msr_count;
     struct vmx_msr_entry **msr_area, *msr_area_elem;
 
-    if ( type == VMX_GUEST_MSR )
-    {
-        msr_count = &curr->arch.hvm_vmx.msr_count;
-        msr_area = &curr->arch.hvm_vmx.msr_area;
-    }
-    else
+    switch ( type )
     {
-        ASSERT(type == VMX_HOST_MSR);
+    case VMX_MSR_HOST:
         msr_count = &curr->arch.hvm_vmx.host_msr_count;
         msr_area = &curr->arch.hvm_vmx.host_msr_area;
+        break;
+
+    case VMX_MSR_GUEST:
+        msr_count = &curr->arch.hvm_vmx.msr_count;
+        msr_area = &curr->arch.hvm_vmx.msr_area;
+        break;
+
+    default:
+        ASSERT_UNREACHABLE();
+        return -EINVAL;
     }
 
     if ( *msr_area == NULL )
@@ -1370,13 +1353,17 @@ int vmx_add_msr(u32 msr, int type)
         if ( (*msr_area = alloc_xenheap_page()) == NULL )
             return -ENOMEM;
 
-        if ( type == VMX_GUEST_MSR )
+        switch ( type )
         {
+        case VMX_MSR_HOST:
+            __vmwrite(VM_EXIT_MSR_LOAD_ADDR, virt_to_maddr(*msr_area));
+            break;
+
+        case VMX_MSR_GUEST:
             __vmwrite(VM_EXIT_MSR_STORE_ADDR, virt_to_maddr(*msr_area));
             __vmwrite(VM_ENTRY_MSR_LOAD_ADDR, virt_to_maddr(*msr_area));
+            break;
         }
-        else
-            __vmwrite(VM_EXIT_MSR_LOAD_ADDR, virt_to_maddr(*msr_area));
     }
 
     for ( idx = 0; idx < *msr_count && (*msr_area)[idx].index <= msr; idx++ )
@@ -1395,16 +1382,18 @@ int vmx_add_msr(u32 msr, int type)
 
     ++*msr_count;
 
-    if ( type == VMX_GUEST_MSR )
+    switch ( type )
     {
+    case VMX_MSR_HOST:
+        rdmsrl(msr, msr_area_elem->data);
+        __vmwrite(VM_EXIT_MSR_LOAD_COUNT, *msr_count);
+        break;
+
+    case VMX_MSR_GUEST:
         msr_area_elem->data = 0;
         __vmwrite(VM_EXIT_MSR_STORE_COUNT, *msr_count);
         __vmwrite(VM_ENTRY_MSR_LOAD_COUNT, *msr_count);
-    }
-    else
-    {
-        rdmsrl(msr, msr_area_elem->data);
-        __vmwrite(VM_EXIT_MSR_LOAD_COUNT, *msr_count);
+        break;
     }
 
     return 0;
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -4196,7 +4196,7 @@ static void lbr_tsx_fixup(void)
     struct vmx_msr_entry *msr_area = curr->arch.hvm_vmx.msr_area;
     struct vmx_msr_entry *msr;
 
-    if ( (msr = vmx_find_msr(lbr_from_start, VMX_GUEST_MSR)) != NULL )
+    if ( (msr = vmx_find_msr(lbr_from_start, VMX_MSR_GUEST)) != NULL )
     {
         /*
          * Sign extend into bits 61:62 while preserving bit 63
@@ -4206,7 +4206,7 @@ static void lbr_tsx_fixup(void)
             msr->data |= ((LBR_FROM_SIGNEXT_2MSB & msr->data) << 2);
     }
 
-    if ( (msr = vmx_find_msr(lbr_lastint_from, VMX_GUEST_MSR)) != NULL )
+    if ( (msr = vmx_find_msr(lbr_lastint_from, VMX_MSR_GUEST)) != NULL )
         msr->data |= ((LBR_FROM_SIGNEXT_2MSB & msr->data) << 2);
 }
 
@@ -4234,8 +4234,8 @@ static void bdw_erratum_bdf14_fixup(void
      * erratum BDF14. Fix up MSR_IA32_LASTINT{FROM,TO}IP by
      * sign-extending into bits 48:63.
      */
-    sign_extend_msr(MSR_IA32_LASTINTFROMIP, VMX_GUEST_MSR);
-    sign_extend_msr(MSR_IA32_LASTINTTOIP, VMX_GUEST_MSR);
+    sign_extend_msr(MSR_IA32_LASTINTFROMIP, VMX_MSR_GUEST);
+    sign_extend_msr(MSR_IA32_LASTINTTOIP, VMX_MSR_GUEST);
 }
 
 static void lbr_fixup(void)
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -511,9 +511,6 @@ enum vmcs_field {
 
 #define VMCS_VPID_WIDTH 16
 
-#define VMX_GUEST_MSR 0
-#define VMX_HOST_MSR  1
-
 /* VM Instruction error numbers */
 enum vmx_insn_errno
 {
@@ -531,6 +528,52 @@ enum vmx_insn_errno
     VMX_INSN_FAIL_INVALID                  = ~0,
 };
 
+/* MSR load/save list infrastructure. */
+enum vmx_msr_list_type {
+    VMX_MSR_HOST,           /* MSRs loaded on VMExit.                   */
+    VMX_MSR_GUEST,          /* MSRs saved on VMExit, loaded on VMEntry. */
+};
+
+int vmx_add_msr(uint32_t msr, enum vmx_msr_list_type type);
+
+static inline int vmx_add_host_load_msr(uint32_t msr)
+{
+    return vmx_add_msr(msr, VMX_MSR_HOST);
+}
+
+static inline int vmx_add_guest_msr(uint32_t msr)
+{
+    return vmx_add_msr(msr, VMX_MSR_GUEST);
+}
+
+struct vmx_msr_entry *vmx_find_msr(uint32_t msr, enum vmx_msr_list_type type);
+
+static inline int vmx_read_guest_msr(uint32_t msr, uint64_t *val)
+{
+    const struct vmx_msr_entry *ent = vmx_find_msr(msr, VMX_MSR_GUEST);
+
+    if ( !ent )
+        return -ESRCH;
+
+    *val = ent->data;
+
+    return 0;
+}
+
+static inline int vmx_write_guest_msr(uint32_t msr, uint64_t val)
+{
+    struct vmx_msr_entry *ent = vmx_find_msr(msr, VMX_MSR_GUEST);
+
+    if ( !ent )
+        return -ESRCH;
+
+    ent->data = val;
+
+    return 0;
+}
+
+
+/* MSR intercept bitmap infrastructure. */
 enum vmx_msr_intercept_type {
     VMX_MSR_R  = 1,
     VMX_MSR_W  = 2,
@@ -541,10 +584,6 @@ void vmx_clear_msr_intercept(struct vcpu
                              enum vmx_msr_intercept_type type);
 void vmx_set_msr_intercept(struct vcpu *v, unsigned int msr,
                            enum vmx_msr_intercept_type type);
-int vmx_read_guest_msr(u32 msr, u64 *val);
-int vmx_write_guest_msr(u32 msr, u64 val);
-struct vmx_msr_entry *vmx_find_msr(u32 msr, int type);
-int vmx_add_msr(u32 msr, int type);
 void vmx_vmcs_switch(paddr_t from, paddr_t to);
 void vmx_set_eoi_exit_bitmap(struct vcpu *v, u8 vector);
 void vmx_clear_eoi_exit_bitmap(struct vcpu *v, u8 vector);
@@ -559,15 +598,6 @@ void virtual_vmcs_vmwrite(const struct v
 enum vmx_insn_errno virtual_vmcs_vmwrite_safe(const struct vcpu *v,
                                               u32 vmcs_encoding, u64 val);
 
-static inline int vmx_add_guest_msr(u32 msr)
-{
-    return vmx_add_msr(msr, VMX_GUEST_MSR);
-}
-static inline int vmx_add_host_load_msr(u32 msr)
-{
-    return vmx_add_msr(msr, VMX_HOST_MSR);
-}
-
 DECLARE_PER_CPU(bool_t, vmxon);
 
 bool_t vmx_vcpu_pml_enabled(const struct vcpu *v);
