[kvm-unit-tests v3 PATCH 3/3] vmx: Correctly refresh EPTP value in EPT accessed and dirty flag test

[Cathy Avery <cavery@redhat.com>]

If ept_ad is not supported by the processor or has been
turned off via kvm module param, test_ept_eptp() will
incorrectly leave EPTP_AD_FLAG set in variable eptp
causing the following failures of subsequent
test_vmx_valid_controls calls:

FAIL: Enable-EPT enabled; reserved bits [11:7] 0: vmlaunch succeeds
FAIL: Enable-EPT enabled; reserved bits [63:N] 0: vmlaunch succeeds

Use the saved EPTP to restore the EPTP after each sub-test instead of
manually unwinding what was done by the sub-test, which is error prone
and hard to follow.

Signed-off-by: Cathy Avery <cavery@redhat.com>
---
 x86/vmx_tests.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 617f9dd..1269829 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -4751,8 +4751,7 @@ static void test_ept_eptp(void)
 			test_vmx_invalid_controls();
 		report_prefix_pop();
 	}
-
-	eptp = (eptp & ~EPT_MEM_TYPE_MASK) | 6ul;
+	eptp = eptp_saved;
 
 	/*
 	 * Page walk length (bits 5:3).  Note, the value in VMCS.EPTP "is 1
@@ -4771,9 +4770,7 @@ static void test_ept_eptp(void)
 			test_vmx_invalid_controls();
 		report_prefix_pop();
 	}
-
-	eptp = (eptp & ~EPTP_PG_WALK_LEN_MASK) |
-	    3ul << EPTP_PG_WALK_LEN_SHIFT;
+	eptp = eptp_saved;
 
 	/*
 	 * Accessed and dirty flag (bit 6)
@@ -4793,6 +4790,7 @@ static void test_ept_eptp(void)
 		eptp |= EPTP_AD_FLAG;
 		test_eptp_ad_bit(eptp, false);
 	}
+	eptp = eptp_saved;
 
 	/*
 	 * Reserved bits [11:7] and [63:N]
@@ -4811,8 +4809,7 @@ static void test_ept_eptp(void)
 			test_vmx_invalid_controls();
 		report_prefix_pop();
 	}
-
-	eptp = (eptp & ~(EPTP_RESERV_BITS_MASK << EPTP_RESERV_BITS_SHIFT));
+	eptp = eptp_saved;
 
 	maxphysaddr = cpuid_maxphyaddr();
 	for (i = 0; i < (63 - maxphysaddr + 1); i++) {
@@ -4831,6 +4828,7 @@ static void test_ept_eptp(void)
 			test_vmx_invalid_controls();
 		report_prefix_pop();
 	}
+	eptp = eptp_saved;
 
 	secondary &= ~(CPU_EPT | CPU_URG);
 	vmcs_write(CPU_EXEC_CTRL1, secondary);
-- 
2.31.1