[Xen-devel] [PATCH v3 07/13] VMX: add VMFUNC leaf 0 (EPTP switching) to emulator.

[Ed White <edmund.h.white@xxxxxxxxx>]

From: Ravi Sahita <ravi.sahita@xxxxxxxxx>

Signed-off-by: Ravi Sahita <ravi.sahita@xxxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c             | 12 +++++++--
 xen/arch/x86/hvm/vmx/vmx.c             | 30 +++++++++++++++++++++
 xen/arch/x86/x86_emulate/x86_emulate.c | 48 +++++++++++++++++++++-------------
 xen/arch/x86/x86_emulate/x86_emulate.h |  4 +++
 xen/include/asm-x86/hvm/hvm.h          |  2 ++
 5 files changed, 76 insertions(+), 20 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index ac9c9d6..157fe78 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1356,6 +1356,12 @@ static int hvmemul_invlpg(
     return rc;
 }
 
+static int hvmemul_vmfunc(
+    struct x86_emulate_ctxt *ctxt)
+{
+    return hvm_funcs.ap2m_vcpu_emulate_vmfunc(ctxt->regs);
+}
+
 static const struct x86_emulate_ops hvm_emulate_ops = {
     .read          = hvmemul_read,
     .insn_fetch    = hvmemul_insn_fetch,
@@ -1379,7 +1385,8 @@ static const struct x86_emulate_ops hvm_emulate_ops = {
     .inject_sw_interrupt = hvmemul_inject_sw_interrupt,
     .get_fpu       = hvmemul_get_fpu,
     .put_fpu       = hvmemul_put_fpu,
-    .invlpg        = hvmemul_invlpg
+    .invlpg        = hvmemul_invlpg,
+    .vmfunc        = hvmemul_vmfunc,
 };
 
 static const struct x86_emulate_ops hvm_emulate_ops_no_write = {
@@ -1405,7 +1412,8 @@ static const struct x86_emulate_ops 
hvm_emulate_ops_no_write = {
     .inject_sw_interrupt = hvmemul_inject_sw_interrupt,
     .get_fpu       = hvmemul_get_fpu,
     .put_fpu       = hvmemul_put_fpu,
-    .invlpg        = hvmemul_invlpg
+    .invlpg        = hvmemul_invlpg,
+    .vmfunc        = hvmemul_vmfunc,
 };
 
 static int _hvm_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt,
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 9585aa3..c6feeae 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -82,6 +82,7 @@ static void vmx_fpu_dirty_intercept(void);
 static int vmx_msr_read_intercept(unsigned int msr, uint64_t *msr_content);
 static int vmx_msr_write_intercept(unsigned int msr, uint64_t msr_content);
 static void vmx_invlpg_intercept(unsigned long vaddr);
+static int vmx_vmfunc_intercept(struct cpu_user_regs *regs);
 
 uint8_t __read_mostly posted_intr_vector;
 
@@ -1830,6 +1831,20 @@ static void vmx_vcpu_update_vmfunc_ve(struct vcpu *v)
     vmx_vmcs_exit(v);
 }
 
+static int vmx_vcpu_emulate_vmfunc(struct cpu_user_regs *regs)
+{
+    int rc = X86EMUL_EXCEPTION;
+    struct vcpu *v = current;
+
+    if ( !cpu_has_vmx_vmfunc && altp2m_active(v->domain) &&
+         regs->eax == 0 &&
+         p2m_switch_vcpu_altp2m_by_id(v, (uint16_t)regs->ecx) )
+    {
+        rc = X86EMUL_OKAY;
+    }
+    return rc;
+}
+
 static bool_t vmx_vcpu_emulate_ve(struct vcpu *v)
 {
     bool_t rc = 0;
@@ -1898,6 +1913,7 @@ static struct hvm_function_table __initdata 
vmx_function_table = {
     .msr_read_intercept   = vmx_msr_read_intercept,
     .msr_write_intercept  = vmx_msr_write_intercept,
     .invlpg_intercept     = vmx_invlpg_intercept,
+    .vmfunc_intercept     = vmx_vmfunc_intercept,
     .handle_cd            = vmx_handle_cd,
     .set_info_guest       = vmx_set_info_guest,
     .set_rdtsc_exiting    = vmx_set_rdtsc_exiting,
@@ -1924,6 +1940,7 @@ static struct hvm_function_table __initdata 
vmx_function_table = {
     .ap2m_vcpu_update_eptp = vmx_vcpu_update_eptp,
     .ap2m_vcpu_update_vmfunc_ve = vmx_vcpu_update_vmfunc_ve,
     .ap2m_vcpu_emulate_ve = vmx_vcpu_emulate_ve,
+    .ap2m_vcpu_emulate_vmfunc = vmx_vcpu_emulate_vmfunc,
 };
 
 const struct hvm_function_table * __init start_vmx(void)
@@ -2095,6 +2112,12 @@ static void vmx_invlpg_intercept(unsigned long vaddr)
         vpid_sync_vcpu_gva(curr, vaddr);
 }
 
+static int vmx_vmfunc_intercept(struct cpu_user_regs *regs)
+{
+    gdprintk(XENLOG_ERR, "Failed guest VMFUNC execution\n");
+    return X86EMUL_EXCEPTION;
+}
+
 static int vmx_cr_access(unsigned long exit_qualification)
 {
     struct vcpu *curr = current;
@@ -3245,6 +3268,13 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
             update_guest_eip();
         break;
 
+    case EXIT_REASON_VMFUNC:
+        if ( vmx_vmfunc_intercept(regs) == X86EMUL_OKAY )
+            update_guest_eip();
+        else
+            hvm_inject_hw_exception(TRAP_invalid_op, 
HVM_DELIVER_NO_ERROR_CODE);
+        break;
+
     case EXIT_REASON_MWAIT_INSTRUCTION:
     case EXIT_REASON_MONITOR_INSTRUCTION:
     case EXIT_REASON_GETSEC:
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index c017c69..adf64d0 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -3815,28 +3815,40 @@ x86_emulate(
     case 0x01: /* Grp7 */ {
         struct segment_register reg;
         unsigned long base, limit, cr0, cr0w;
+        uint64_t tsc_aux;
 
-        if ( modrm == 0xdf ) /* invlpga */
+        switch( modrm )
         {
-            generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
-            generate_exception_if(!mode_ring0(), EXC_GP, 0);
-            fail_if(ops->invlpg == NULL);
-            if ( (rc = ops->invlpg(x86_seg_none, truncate_ea(_regs.eax),
-                                   ctxt)) )
-                goto done;
-            break;
-        }
-
-        if ( modrm == 0xf9 ) /* rdtscp */
-        {
-            uint64_t tsc_aux;
-            fail_if(ops->read_msr == NULL);
-            if ( (rc = ops->read_msr(MSR_TSC_AUX, &tsc_aux, ctxt)) != 0 )
-                goto done;
-            _regs.ecx = (uint32_t)tsc_aux;
-            goto rdtsc;
+            case 0xdf: /* invlpga AMD */
+                generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
+                generate_exception_if(!mode_ring0(), EXC_GP, 0);
+                fail_if(ops->invlpg == NULL);
+                if ( (rc = ops->invlpg(x86_seg_none, truncate_ea(_regs.eax),
+                                       ctxt)) )
+                    goto done;
+                break;
+            case 0xf9: /* rdtscp */
+                fail_if(ops->read_msr == NULL);
+                if ( (rc = ops->read_msr(MSR_TSC_AUX, &tsc_aux, ctxt)) != 0 )
+                    goto done;
+                _regs.ecx = (uint32_t)tsc_aux;
+                goto rdtsc;
+            case 0xd4: /* vmfunc */
+                generate_exception_if(
+                    (lock_prefix |
+                    rep_prefix() |
+                    (vex.pfx == vex_66)),
+                    EXC_UD, -1);
+                fail_if(ops->vmfunc == NULL);
+                if ( (rc = ops->vmfunc(ctxt) != X86EMUL_OKAY) )
+                    goto done;
+                break;
+            default:
+                goto continue_grp7;
         }
+        break;
 
+continue_grp7:
         switch ( modrm_reg & 7 )
         {
         case 0: /* sgdt */
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.h 
b/xen/arch/x86/x86_emulate/x86_emulate.h
index 064b8f4..a4d4ec8 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.h
+++ b/xen/arch/x86/x86_emulate/x86_emulate.h
@@ -397,6 +397,10 @@ struct x86_emulate_ops
         enum x86_segment seg,
         unsigned long offset,
         struct x86_emulate_ctxt *ctxt);
+
+    /* vmfunc: Emulate VMFUNC via given set of EAX ECX inputs */
+    int (*vmfunc)(
+        struct x86_emulate_ctxt *ctxt);
 };
 
 struct cpu_user_regs;
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 36f1b74..595b399 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -167,6 +167,7 @@ struct hvm_function_table {
     int (*msr_read_intercept)(unsigned int msr, uint64_t *msr_content);
     int (*msr_write_intercept)(unsigned int msr, uint64_t msr_content);
     void (*invlpg_intercept)(unsigned long vaddr);
+    int (*vmfunc_intercept)(struct cpu_user_regs *regs);
     void (*handle_cd)(struct vcpu *v, unsigned long value);
     void (*set_info_guest)(struct vcpu *v);
     void (*set_rdtsc_exiting)(struct vcpu *v, bool_t);
@@ -218,6 +219,7 @@ struct hvm_function_table {
     void (*ap2m_vcpu_update_eptp)(struct vcpu *v);
     void (*ap2m_vcpu_update_vmfunc_ve)(struct vcpu *v);
     bool_t (*ap2m_vcpu_emulate_ve)(struct vcpu *v);
+    int (*ap2m_vcpu_emulate_vmfunc)(struct cpu_user_regs *regs);
 };
 
 extern struct hvm_function_table hvm_funcs;
-- 
1.9.1


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