[PATCH kvm-unit-tests 0/4] test GUEST_EFER field and address size controls

[PATCH kvm-unit-tests 0/4] test GUEST_EFER field and address size controls

[Paolo Bonzini]

This series extends the HOST_EFER tests to test the host address size
(patch 2) and adds matching tests for GUEST_EFER (patches 3-4).

Paolo Bonzini (4):
  x86: vmx_tests: gate load guest PAT tests on the correct bit
  x86: vmx_tests: extend HOST_EFER tests
  x86: vmx_tests: prepare for extending guest state area tests
  x86: vmx_tests: add GUEST_EFER tests

 x86/vmx_tests.c | 219 +++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 145 insertions(+), 74 deletions(-)

-- 
1.8.3.1

[PATCH kvm-unit-tests 1/4] x86: vmx_tests: gate load guest PAT tests on the correct bit

[Paolo Bonzini]

The tests should check the "load PAT" entry control,
not the exit control.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 x86/vmx_tests.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index a447d39..b404219 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -7203,7 +7203,7 @@ static void test_load_guest_pat(void)
 	/*
 	 * "load IA32_PAT" VM-entry control
 	 */
-	if (!(ctrl_exit_rev.clr & ENT_LOAD_PAT)) {
+	if (!(ctrl_enter_rev.clr & ENT_LOAD_PAT)) {
 		printf("\"Load-IA32-PAT\" entry control not supported\n");
 		return;
 	}
-- 
1.8.3.1

[PATCH kvm-unit-tests 2/4] x86: vmx_tests: extend HOST_EFER tests

[Paolo Bonzini]

Extend the tests to cover the host address size bit.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 x86/vmx_tests.c | 126 +++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 74 insertions(+), 52 deletions(-)

diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index b404219..8851f64 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -6720,59 +6720,62 @@ static void test_host_ctl_regs(void)
 	vmcs_write(HOST_CR3, cr3_saved);
 }
 
-static void test_efer_bit(u32 fld, const char * fld_name, u32 ctrl_fld,
-			   u64 ctrl_bit, u64 efer_bit,
-			   const char *efer_bit_name)
+static void test_efer_one(u32 fld, const char * fld_name, u64 efer,
+			  u32 ctrl_fld, u64 ctrl,
+			  int i, const char *efer_bit_name)
 {
-	u64 efer_saved = vmcs_read(fld);
-	u32 ctrl_saved = vmcs_read(ctrl_fld);
-	u64 host_addr_size = ctrl_saved & EXI_HOST_64;
-	u64 efer;
+	bool ok;
 
-	vmcs_write(ctrl_fld, ctrl_saved & ~ctrl_bit);
-	efer = efer_saved & ~efer_bit;
-	vmcs_write(fld, efer);
-	report_prefix_pushf("%s bit turned off, %s %lx", efer_bit_name,
-			    fld_name, efer);
-	test_vmx_vmlaunch(0, false);
-	report_prefix_pop();
+	ok = true;
+	if (ctrl & EXI_LOAD_EFER) {
+		if (!!(efer & EFER_LMA) != !!(ctrl & EXI_HOST_64))
+			ok = false;
+		if (!!(efer & EFER_LME) != !!(ctrl & EXI_HOST_64))
+			ok = false;
+	}
 
-	efer = efer_saved | efer_bit;
+	vmcs_write(ctrl_fld, ctrl);
 	vmcs_write(fld, efer);
-	report_prefix_pushf("%s bit turned on, %s %lx", efer_bit_name,
-			    fld_name, efer);
-	test_vmx_vmlaunch(0, false);
-	report_prefix_pop();
+	report_prefix_pushf("%s %s bit turned %s, controls %s",
+			    fld_name, efer_bit_name,
+			    (i & 1) ? "on" : "off",
+			    (i & 2) ? "on" : "off");
 
-	vmcs_write(ctrl_fld, ctrl_saved | ctrl_bit);
-	efer = efer_saved & ~efer_bit;
-	vmcs_write(fld, efer);
-	report_prefix_pushf("%s bit turned off, %s %lx", efer_bit_name,
-			    fld_name, efer);
-	if (host_addr_size)
-		test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
-				  false);
-	else
-		test_vmx_vmlaunch(0, false);
-	report_prefix_pop();
-
-	efer = efer_saved | efer_bit;
-	vmcs_write(fld, efer);
-	report_prefix_pushf("%s bit turned on, %s %lx", efer_bit_name,
-			    fld_name, efer);
-	if (host_addr_size)
+	if (ok)
 		test_vmx_vmlaunch(0, false);
 	else
 		test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
 				  false);
 	report_prefix_pop();
+}
+
+static void test_efer_bit(u32 fld, const char * fld_name,
+			  u32 ctrl_fld, u64 ctrl_bit, u64 efer_bit,
+			  const char *efer_bit_name)
+{
+	u64 efer_saved = vmcs_read(fld);
+	u32 ctrl_saved = vmcs_read(ctrl_fld);
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		u64 efer = efer_saved & ~efer_bit;
+		u64 ctrl = ctrl_saved & ~ctrl_bit;
+
+		if (i & 1)
+			efer |= efer_bit;
+		if (i & 2)
+			ctrl |= ctrl_bit;
+
+		test_efer_one(fld, fld_name, efer, ctrl_fld, ctrl,
+			      i, efer_bit_name);
+	}
 
 	vmcs_write(ctrl_fld, ctrl_saved);
 	vmcs_write(fld, efer_saved);
 }
 
 static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
-		      u64 ctrl_bit)
+		      u64 ctrl_bit1, u64 ctrl_bit2)
 {
 	u64 efer_saved = vmcs_read(fld);
 	u32 ctrl_saved = vmcs_read(ctrl_fld);
@@ -6783,10 +6786,19 @@ static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
 	if (cpu_has_efer_nx())
 		efer_reserved_bits &= ~EFER_NX;
 
+	if (!ctrl_bit1) {
+		printf("\"Load-IA32-EFER\" exit control not supported\n");
+		goto test_entry_exit_mode;
+	}
+
+	report_prefix_pushf("%s %lx", fld_name, efer_saved);
+	test_vmx_vmlaunch(0, false);
+	report_prefix_pop();
+
 	/*
 	 * Check reserved bits
 	 */
-	vmcs_write(ctrl_fld, ctrl_saved & ~ctrl_bit);
+	vmcs_write(ctrl_fld, ctrl_saved & ~ctrl_bit1);
 	for (i = 0; i < 64; i++) {
 		if ((1ull << i) & efer_reserved_bits) {
 			efer = efer_saved | (1ull << i);
@@ -6797,15 +6809,14 @@ static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
 		}
 	}
 
-	vmcs_write(ctrl_fld, ctrl_saved | ctrl_bit);
+	vmcs_write(ctrl_fld, ctrl_saved | ctrl_bit1);
 	for (i = 0; i < 64; i++) {
 		if ((1ull << i) & efer_reserved_bits) {
 			efer = efer_saved | (1ull << i);
 			vmcs_write(fld, efer);
 			report_prefix_pushf("%s %lx", fld_name, efer);
-			test_vmx_vmlaunch(
-				VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
-				false);
+			test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
+					  false);
 			report_prefix_pop();
 		}
 	}
@@ -6816,28 +6827,39 @@ static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
 	/*
 	 * Check LMA and LME bits
 	 */
-	test_efer_bit(fld, fld_name, ctrl_fld, ctrl_bit, EFER_LMA,
+	test_efer_bit(fld, fld_name,
+		      ctrl_fld, ctrl_bit1,
+		      EFER_LMA,
+		      "EFER_LMA");
+	test_efer_bit(fld, fld_name,
+		      ctrl_fld, ctrl_bit1,
+		      EFER_LME,
+		      "EFER_LME");
+
+test_entry_exit_mode:
+	test_efer_bit(fld, fld_name,
+		      ctrl_fld, ctrl_bit2,
+		      EFER_LMA,
 		      "EFER_LMA");
-	test_efer_bit(fld, fld_name, ctrl_fld, ctrl_bit, EFER_LME,
+	test_efer_bit(fld, fld_name,
+		      ctrl_fld, ctrl_bit2,
+		      EFER_LME,
 		      "EFER_LME");
 }
 
 /*
- * If the “load IA32_EFER†VM-exit control is 1, bits reserved in the
+ * If the 'load IA32_EFER' VM-exit control is 1, bits reserved in the
  * IA32_EFER MSR must be 0 in the field for that register. In addition,
  * the values of the LMA and LME bits in the field must each be that of
- * the “host address-space size†VM-exit control.
+ * the 'host address-space size' VM-exit control.
  *
  *  [Intel SDM]
  */
 static void test_host_efer(void)
 {
-	if (!(ctrl_exit_rev.clr & EXI_LOAD_EFER)) {
-		printf("\"Load-IA32-EFER\" exit control not supported\n");
-		return;
-	}
-
-	test_efer(HOST_EFER, "HOST_EFER", EXI_CONTROLS, EXI_LOAD_EFER);
+	test_efer(HOST_EFER, "HOST_EFER", EXI_CONTROLS, 
+		  ctrl_exit_rev.clr & EXI_LOAD_EFER,
+		  EXI_HOST_64);
 }
 
 /*
-- 
1.8.3.1

[PATCH kvm-unit-tests 3/4] x86: vmx_tests: prepare for extending guest state area tests

[Paolo Bonzini]

Move the test setup and teardown from test_pat to vmx_guest_state_area_test,
so that we can add more tests after test_load_guest_pat.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 x86/vmx_tests.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 8851f64..97aff6e 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -6879,10 +6879,6 @@ static void test_pat(u32 field, const char * field_name, u32 ctrl_field,
 	int error;
 
 	vmcs_clear_bits(ctrl_field, ctrl_bit);
-	if (field == GUEST_PAT) {
-		vmx_set_test_stage(1);
-		test_set_guest(guest_state_test_main);
-	}
 
 	for (i = 0; i < 256; i = (i < PAT_VAL_LIMIT) ? i + 1 : i * 2) {
 		/* Test PAT0..PAT7 fields */
@@ -6942,15 +6938,6 @@ static void test_pat(u32 field, const char * field_name, u32 ctrl_field,
 		}
 	}
 
-	if (field == GUEST_PAT) {
-		/*
-		 * Let the guest finish execution
-		 */
-		vmx_set_test_stage(2);
-		vmcs_write(field, pat_saved);
-		enter_guest();
-	}
-
 	vmcs_write(ctrl_field, ctrl_saved);
 	vmcs_write(field, pat_saved);
 }
@@ -7239,7 +7226,16 @@ static void test_load_guest_pat(void)
  */
 static void vmx_guest_state_area_test(void)
 {
+	vmx_set_test_stage(1);
+	test_set_guest(guest_state_test_main);
+
 	test_load_guest_pat();
+
+	/*
+	 * Let the guest finish execution
+	 */
+	vmx_set_test_stage(2);
+	enter_guest();
 }
 
 static bool valid_vmcs_for_vmentry(void)
-- 
1.8.3.1

[PATCH kvm-unit-tests 4/4] x86: vmx_tests: add GUEST_EFER tests

[Paolo Bonzini]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Conflicts:
	x86/vmx_tests.c
---
 x86/vmx_tests.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 70 insertions(+), 17 deletions(-)

diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 97aff6e..dba61a3 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -5030,19 +5030,23 @@ static void guest_state_test_main(void)
 	asm volatile("fnop");
 }
 
+static void advance_guest_state_test(void)
+{
+	u32 reason = vmcs_read(EXI_REASON);
+	if (! (reason & 0x80000000)) {
+		u64 guest_rip = vmcs_read(GUEST_RIP);
+		u32 insn_len = vmcs_read(EXI_INST_LEN);
+		vmcs_write(GUEST_RIP, guest_rip + insn_len);
+	}
+}
+
 static void report_guest_state_test(const char *test, u32 xreason,
 				    u64 field, const char * field_name)
 {
 	u32 reason = vmcs_read(EXI_REASON);
-	u64 guest_rip;
-	u32 insn_len;
 
 	report("%s, %s %lx", reason == xreason, test, field_name, field);
-
-	guest_rip = vmcs_read(GUEST_RIP);
-	insn_len = vmcs_read(EXI_INST_LEN);
-	if (! (reason & 0x80000021))
-		vmcs_write(GUEST_RIP, guest_rip + insn_len);
+	advance_guest_state_test();
 }
 
 /*
@@ -6720,6 +6724,25 @@ static void test_host_ctl_regs(void)
 	vmcs_write(HOST_CR3, cr3_saved);
 }
 
+static void test_efer_vmlaunch(u32 fld, bool ok)
+{
+	if (fld == HOST_EFER) {
+		if (ok)
+			test_vmx_vmlaunch(0, false);
+		else
+			test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD, false);
+	} else {
+		if (ok) {
+			enter_guest();
+			report("vmlaunch succeeds", vmcs_read(EXI_REASON) == VMX_VMCALL);
+		} else {
+			enter_guest_with_invalid_guest_state();
+			report("vmlaunch fails", vmcs_read(EXI_REASON) == (VMX_ENTRY_FAILURE | VMX_FAIL_STATE));
+		}
+		advance_guest_state_test();
+	}
+}
+
 static void test_efer_one(u32 fld, const char * fld_name, u64 efer,
 			  u32 ctrl_fld, u64 ctrl,
 			  int i, const char *efer_bit_name)
@@ -6727,12 +6750,27 @@ static void test_efer_one(u32 fld, const char * fld_name, u64 efer,
 	bool ok;
 
 	ok = true;
-	if (ctrl & EXI_LOAD_EFER) {
+	if (ctrl_fld == EXI_CONTROLS && (ctrl & EXI_LOAD_EFER)) {
 		if (!!(efer & EFER_LMA) != !!(ctrl & EXI_HOST_64))
 			ok = false;
 		if (!!(efer & EFER_LME) != !!(ctrl & EXI_HOST_64))
 			ok = false;
 	}
+	if (ctrl_fld == ENT_CONTROLS && (ctrl & ENT_LOAD_EFER)) {
+		/* Check LMA too since CR0.PG is set.  */
+		if (!!(efer & EFER_LMA) != !!(ctrl & ENT_GUEST_64))
+			ok = false;
+		if (!!(efer & EFER_LME) != !!(ctrl & ENT_GUEST_64))
+			ok = false;
+	}
+
+	/*
+	 * Skip the test if it would enter the guest in 32-bit mode.
+	 * Perhaps write the test in assembly and make sure it
+	 * can be run in either mode?
+	 */
+	if (fld == GUEST_EFER && ok && !(ctrl & ENT_GUEST_64))
+		return;
 
 	vmcs_write(ctrl_fld, ctrl);
 	vmcs_write(fld, efer);
@@ -6741,11 +6779,7 @@ static void test_efer_one(u32 fld, const char * fld_name, u64 efer,
 			    (i & 1) ? "on" : "off",
 			    (i & 2) ? "on" : "off");
 
-	if (ok)
-		test_vmx_vmlaunch(0, false);
-	else
-		test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
-				  false);
+	test_efer_vmlaunch(fld, ok);
 	report_prefix_pop();
 }
 
@@ -6792,7 +6826,7 @@ static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
 	}
 
 	report_prefix_pushf("%s %lx", fld_name, efer_saved);
-	test_vmx_vmlaunch(0, false);
+	test_efer_vmlaunch(fld, true);
 	report_prefix_pop();
 
 	/*
@@ -6804,7 +6838,7 @@ static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
 			efer = efer_saved | (1ull << i);
 			vmcs_write(fld, efer);
 			report_prefix_pushf("%s %lx", fld_name, efer);
-			test_vmx_vmlaunch(0, false);
+			test_efer_vmlaunch(fld, true);
 			report_prefix_pop();
 		}
 	}
@@ -6815,8 +6849,7 @@ static void test_efer(u32 fld, const char * fld_name, u32 ctrl_fld,
 			efer = efer_saved | (1ull << i);
 			vmcs_write(fld, efer);
 			report_prefix_pushf("%s %lx", fld_name, efer);
-			test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
-					  false);
+			test_efer_vmlaunch(fld, false);
 			report_prefix_pop();
 		}
 	}
@@ -6863,6 +6896,25 @@ static void test_host_efer(void)
 }
 
 /*
+ * If the 'load IA32_EFER' VM-enter control is 1, bits reserved in the
+ * IA32_EFER MSR must be 0 in the field for that register. In addition,
+ * the values of the LMA and LME bits in the field must each be that of
+ * the 'IA32e-mode guest' VM-exit control.
+ */
+static void test_guest_efer(void)
+{
+	if (!(ctrl_enter_rev.clr & ENT_LOAD_EFER)) {
+		printf("\"Load-IA32-EFER\" entry control not supported\n");
+		return;
+	}
+
+	vmcs_write(GUEST_EFER, rdmsr(MSR_EFER));
+	test_efer(GUEST_EFER, "GUEST_EFER", ENT_CONTROLS,
+		  ctrl_enter_rev.clr & ENT_LOAD_EFER,
+		  ENT_GUEST_64);
+}
+
+/*
  * PAT values higher than 8 are uninteresting since they're likely lumped
  * in with "8". We only test values above 8 one bit at a time,
  * in order to reduce the number of VM-Entries and keep the runtime reasonable.
@@ -7230,6 +7282,7 @@ static void vmx_guest_state_area_test(void)
 	test_set_guest(guest_state_test_main);
 
 	test_load_guest_pat();
+	test_guest_efer();
 
 	/*
 	 * Let the guest finish execution
-- 
1.8.3.1

Re: [PATCH kvm-unit-tests 2/4] x86: vmx_tests: extend HOST_EFER tests

[Nadav Amit]

> On Sep 25, 2019, at 9:14 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
> Extend the tests to cover the host address size bit.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> x86/vmx_tests.c | 126 +++++++++++++++++++++++++++++++++-----------------------
> 1 file changed, 74 insertions(+), 52 deletions(-)

I get the following results with this test on Skylake bare-metal:

PASS: HOST_EFER EFER_LMA bit turned off, controls off: vmlaunch succeeds
PASS: HOST_EFER EFER_LMA bit turned on, controls off: vmlaunch succeeds
PASS: HOST_EFER EFER_LMA bit turned off, controls on: vmlaunch fails
PASS: HOST_EFER EFER_LMA bit turned off, controls on: VMX inst error is 8 (actual 8)
PASS: HOST_EFER EFER_LMA bit turned on, controls on: vmlaunch succeeds
PASS: HOST_EFER EFER_LME bit turned off, controls off: vmlaunch succeeds
PASS: HOST_EFER EFER_LME bit turned on, controls off: vmlaunch succeeds
PASS: HOST_EFER EFER_LME bit turned off, controls on: vmlaunch fails
PASS: HOST_EFER EFER_LME bit turned off, controls on: VMX inst error is 8 (actual 8)
PASS: HOST_EFER EFER_LME bit turned on, controls on: vmlaunch succeeds
PASS: HOST_EFER EFER_LMA bit turned off, controls off: vmlaunch fails
FAIL: HOST_EFER EFER_LMA bit turned off, controls off: VMX inst error is 8 (actual 7)
PASS: HOST_EFER EFER_LMA bit turned on, controls off: vmlaunch fails
FAIL: HOST_EFER EFER_LMA bit turned on, controls off: VMX inst error is 8 (actual 7)
PASS: HOST_EFER EFER_LMA bit turned off, controls on: vmlaunch fails
PASS: HOST_EFER EFER_LMA bit turned off, controls on: VMX inst error is 8 (actual 8)
PASS: HOST_EFER EFER_LMA bit turned on, controls on: vmlaunch succeeds
PASS: HOST_EFER EFER_LME bit turned off, controls off: vmlaunch fails
FAIL: HOST_EFER EFER_LME bit turned off, controls off: VMX inst error is 8 (actual 7)
PASS: HOST_EFER EFER_LME bit turned on, controls off: vmlaunch fails
FAIL: HOST_EFER EFER_LME bit turned on, controls off: VMX inst error is 8 (actual 7)
PASS: HOST_EFER EFER_LME bit turned off, controls on: vmlaunch fails
PASS: HOST_EFER EFER_LME bit turned off, controls on: VMX inst error is 8 (actual 8)
PASS: HOST_EFER EFER_LME bit turned on, controls on: vmlaunch succeeds

Apparently, turning the controls off, causes some “VM entry with invalid
control field” (7) instead of “VM-entry with invalid host-state field”.

According to the SDM, checks of control fields and host field are not ordered.
But I do not know what exactly causes the failure.

Re: [PATCH kvm-unit-tests 2/4] x86: vmx_tests: extend HOST_EFER tests

[Paolo Bonzini]

On 23/11/19 02:40, Nadav Amit wrote:
> 
> 
>> On Sep 25, 2019, at 9:14 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> Extend the tests to cover the host address size bit.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>> x86/vmx_tests.c | 126 +++++++++++++++++++++++++++++++++-----------------------
>> 1 file changed, 74 insertions(+), 52 deletions(-)
> 
> I get the following results with this test on Skylake bare-metal:
> 
> PASS: HOST_EFER EFER_LMA bit turned off, controls off: vmlaunch succeeds
> PASS: HOST_EFER EFER_LMA bit turned on, controls off: vmlaunch succeeds
> PASS: HOST_EFER EFER_LMA bit turned off, controls on: vmlaunch fails
> PASS: HOST_EFER EFER_LMA bit turned off, controls on: VMX inst error is 8 (actual 8)
> PASS: HOST_EFER EFER_LMA bit turned on, controls on: vmlaunch succeeds
> PASS: HOST_EFER EFER_LME bit turned off, controls off: vmlaunch succeeds
> PASS: HOST_EFER EFER_LME bit turned on, controls off: vmlaunch succeeds
> PASS: HOST_EFER EFER_LME bit turned off, controls on: vmlaunch fails
> PASS: HOST_EFER EFER_LME bit turned off, controls on: VMX inst error is 8 (actual 8)
> PASS: HOST_EFER EFER_LME bit turned on, controls on: vmlaunch succeeds
> PASS: HOST_EFER EFER_LMA bit turned off, controls off: vmlaunch fails
> FAIL: HOST_EFER EFER_LMA bit turned off, controls off: VMX inst error is 8 (actual 7)
> PASS: HOST_EFER EFER_LMA bit turned on, controls off: vmlaunch fails
> FAIL: HOST_EFER EFER_LMA bit turned on, controls off: VMX inst error is 8 (actual 7)
> PASS: HOST_EFER EFER_LMA bit turned off, controls on: vmlaunch fails
> PASS: HOST_EFER EFER_LMA bit turned off, controls on: VMX inst error is 8 (actual 8)
> PASS: HOST_EFER EFER_LMA bit turned on, controls on: vmlaunch succeeds
> PASS: HOST_EFER EFER_LME bit turned off, controls off: vmlaunch fails
> FAIL: HOST_EFER EFER_LME bit turned off, controls off: VMX inst error is 8 (actual 7)
> PASS: HOST_EFER EFER_LME bit turned on, controls off: vmlaunch fails
> FAIL: HOST_EFER EFER_LME bit turned on, controls off: VMX inst error is 8 (actual 7)
> PASS: HOST_EFER EFER_LME bit turned off, controls on: vmlaunch fails
> PASS: HOST_EFER EFER_LME bit turned off, controls on: VMX inst error is 8 (actual 8)
> PASS: HOST_EFER EFER_LME bit turned on, controls on: vmlaunch succeeds
> 
> Apparently, turning the controls off, causes some “VM entry with invalid
> control field” (7) instead of “VM-entry with invalid host-state field”.
> 
> According to the SDM, checks of control fields and host field are not ordered.
> But I do not know what exactly causes the failure.

The failure happens when checking the VM-exit host address size bit
against EFER.LMA.  26.2.2 puts that check under "Checks on Host Control
Registers and MSRs", so technically it would be wrong to return error 7
instead of 8.  However we can relax the test, it's not a big deal.

Paolo