[kvm-unit-tests PATCH 35/39] nVMX: Add helper to check if a memtype is supported for EPT structures

[Sean Christopherson <seanjc@xxxxxxxxxx>]

Add a helper to check if a given memtype can be used for EPT structures,
and use the helper to clean up the EPT test code.  An informational
message is lost along the way, but that's not necessarily a bad thing.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 x86/vmx.h       | 11 +++++++++++
 x86/vmx_tests.c | 33 ++-------------------------------
 2 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/x86/vmx.h b/x86/vmx.h
index d3e95f5..401715c 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -825,6 +825,17 @@ static inline bool is_5_level_ept_supported(void)
 	return ept_vpid.val & EPT_CAP_PWL5;
 }
 
+static inline bool is_ept_memtype_supported(int type)
+{
+	if (type == EPT_MEM_TYPE_UC)
+		return ept_vpid.val & EPT_CAP_UC;
+
+	if (type == EPT_MEM_TYPE_WB)
+		return ept_vpid.val & EPT_CAP_WB;
+
+	return false;
+}
+
 static inline bool is_invept_type_supported(u64 type)
 {
 	if (type < INVEPT_SINGLE || type > INVEPT_GLOBAL)
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 2bfc794..27150cb 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -4712,9 +4712,7 @@ static void test_ept_eptp(void)
 	u64 eptp_saved = vmcs_read(EPTP);
 	u32 primary = primary_saved;
 	u32 secondary = secondary_saved;
-	u64 msr, eptp = eptp_saved;
-	bool un_cache = false;
-	bool wr_bk = false;
+	u64 eptp = eptp_saved;
 	bool ctrl;
 	u32 i, maxphysaddr;
 	u64 j, resv_bits_mask = 0;
@@ -4725,15 +4723,6 @@ static void test_ept_eptp(void)
 		return;
 	}
 
-	/*
-	 * Memory type (bits 2:0)
-	 */
-	msr = rdmsr(MSR_IA32_VMX_EPT_VPID_CAP);
-	if (msr & EPT_CAP_UC)
-		un_cache = true;
-	if (msr & EPT_CAP_WB)
-		wr_bk = true;
-
 	/* Support for 4-level EPT is mandatory. */
 	report(is_4_level_ept_supported(), "4-level EPT support check");
 
@@ -4746,29 +4735,11 @@ static void test_ept_eptp(void)
 	vmcs_write(EPTP, eptp);
 
 	for (i = 0; i < 8; i++) {
-		if (i == 0) {
-			if (un_cache) {
-				report_info("EPT paging structure memory-type is Un-cacheable\n");
-				ctrl = true;
-			} else {
-				ctrl = false;
-			}
-		} else if (i == 6) {
-			if (wr_bk) {
-				report_info("EPT paging structure memory-type is Write-back\n");
-				ctrl = true;
-			} else {
-				ctrl = false;
-			}
-		} else {
-			ctrl = false;
-		}
-
 		eptp = (eptp & ~EPT_MEM_TYPE_MASK) | i;
 		vmcs_write(EPTP, eptp);
 		report_prefix_pushf("Enable-EPT enabled; EPT memory type %lu",
 		    eptp & EPT_MEM_TYPE_MASK);
-		if (ctrl)
+		if (is_ept_memtype_supported(i))
 			test_vmx_valid_controls();
 		else
 			test_vmx_invalid_controls();
-- 
2.34.0.rc2.393.gf8c9666880-goog