[Xen-devel] [PATCH v2 06/12] 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             | 13 +++++++++++--
 xen/arch/x86/hvm/vmx/vmx.c             | 30 ++++++++++++++++++++++++++++++
 xen/arch/x86/x86_emulate/x86_emulate.c |  8 ++++++++
 xen/arch/x86/x86_emulate/x86_emulate.h |  4 ++++
 xen/include/asm-x86/hvm/hvm.h          |  2 ++
 5 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index ac9c9d6..e38a2fe 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1356,6 +1356,13 @@ static int hvmemul_invlpg(
     return rc;
 }
 
+static int hvmemul_vmfunc(
+    struct x86_emulate_ctxt *ctxt)
+{
+    hvm_funcs.ahvm_vcpu_emulate_vmfunc(ctxt->regs);
+    return X86EMUL_OKAY;
+}
+
 static const struct x86_emulate_ops hvm_emulate_ops = {
     .read          = hvmemul_read,
     .insn_fetch    = hvmemul_insn_fetch,
@@ -1379,7 +1386,8 @@ 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 +1413,8 @@ 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 e8d9c82..ad9e9e4 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;
 
@@ -1826,6 +1827,20 @@ static void vmx_vcpu_update_vmfunc_ve(struct vcpu *v)
     vmx_vmcs_exit(v);
 }
 
+static bool_t vmx_vcpu_emulate_vmfunc(struct cpu_user_regs *regs)
+{
+    bool_t rc = 0;
+
+    if ( !cpu_has_vmx_vmfunc && altp2mhvm_active(current->domain) &&
+         regs->eax == 0 &&
+         p2m_switch_vcpu_altp2m_by_id(current, (uint16_t)regs->ecx) )
+    {
+        regs->eip += 3;
+        rc = 1;
+    }
+    return rc;
+}
+
 static bool_t vmx_vcpu_emulate_ve(struct vcpu *v)
 {
     bool_t rc = 0;
@@ -1894,6 +1909,7 @@ 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,
@@ -1920,6 +1936,7 @@ static struct hvm_function_table __initdata 
vmx_function_table = {
     .ahvm_vcpu_update_eptp = vmx_vcpu_update_eptp,
     .ahvm_vcpu_update_vmfunc_ve = vmx_vcpu_update_vmfunc_ve,
     .ahvm_vcpu_emulate_ve = vmx_vcpu_emulate_ve,
+    .ahvm_vcpu_emulate_vmfunc = vmx_vcpu_emulate_vmfunc,
 };
 
 const struct hvm_function_table * __init start_vmx(void)
@@ -2091,6 +2108,13 @@ 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");
+    domain_crash(current->domain);
+    return X86EMUL_OKAY;
+}
+
 static int vmx_cr_access(unsigned long exit_qualification)
 {
     struct vcpu *curr = current;
@@ -2675,6 +2699,7 @@ void vmx_enter_realmode(struct cpu_user_regs *regs)
     regs->eflags |= (X86_EFLAGS_VM | X86_EFLAGS_IOPL);
 }
 
+
 static void vmx_vmexit_ud_intercept(struct cpu_user_regs *regs)
 {
     struct hvm_emulate_ctxt ctxt;
@@ -3239,6 +3264,11 @@ 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();
+        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..4ae95ce 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -3837,6 +3837,14 @@ x86_emulate(
             goto rdtsc;
         }
 
+        if (modrm == 0xd4) /* vmfunc */
+        {
+            fail_if(ops->vmfunc == NULL);
+            if ( (rc = ops->vmfunc(ctxt) != 0) )
+                goto done;
+            break;
+        }
+
         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 9cd674f..2e33b4f 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 (*ahvm_vcpu_update_eptp)(struct vcpu *v);
     void (*ahvm_vcpu_update_vmfunc_ve)(struct vcpu *v);
     bool_t (*ahvm_vcpu_emulate_ve)(struct vcpu *v);
+    bool_t (*ahvm_vcpu_emulate_vmfunc)(struct cpu_user_regs *regs);
 };
 
 extern struct hvm_function_table hvm_funcs;
-- 
1.9.1


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