[PATCH][kvm-unit-tests] nEPT: Fix test cases for 2M huge pages

[Jan Kiszka <jan.kiszka@siemens.com>]

If 2M pages are available with EPT, the test code creates its initial
identity map with such pages. But then it tries to remap two 4K pages in
that range which fails as their level 3 PTE is set up for huge pages.

Fix this up by ensuring that install_ept_entry always create non-large
page directory entries and by remapping the 2M area around those two
test pages in 4K chunks.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 x86/vmx.c       | 3 ++-
 x86/vmx.h       | 3 ++-
 x86/vmx_tests.c | 8 ++++++++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/x86/vmx.c b/x86/vmx.c
index 9db4ef4..3e6fc37 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -173,7 +173,8 @@ void install_ept_entry(unsigned long *pml4,
 			memset(new_pt, 0, PAGE_SIZE);
 			pt[offset] = virt_to_phys(new_pt)
 					| EPT_RA | EPT_WA | EPT_EA;
-		}
+		} else
+			pt[offset] &= ~EPT_LARGE_PAGE;
 		pt = phys_to_virt(pt[offset] & 0xffffffffff000ull);
 	}
 	offset = ((unsigned long)guest_addr >> ((level-1) *
diff --git a/x86/vmx.h b/x86/vmx.h
index dc1ebdf..7d967eb 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -485,7 +485,8 @@ enum Ctrl1 {
 #define	EPT_PAGE_LEVEL	4
 #define	EPT_PGDIR_WIDTH	9
 #define	EPT_PGDIR_MASK	511
-#define PAGE_MASK (~(PAGE_SIZE-1))
+#define PAGE_MASK		(~(PAGE_SIZE-1))
+#define PAGE_MASK_2M		(~(PAGE_SIZE_2M-1))
 
 #define EPT_VLT_RD		1
 #define EPT_VLT_WR		(1 << 1)
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 0759e10..a002a7a 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -915,6 +915,7 @@ static int setup_ept()
 
 static void ept_init()
 {
+	unsigned long base_addr1, base_addr2;
 	u32 ctrl_cpu[2];
 
 	init_fail = false;
@@ -934,6 +935,13 @@ static void ept_init()
 	memset(data_page2, 0x0, PAGE_SIZE);
 	*((u32 *)data_page1) = MAGIC_VAL_1;
 	*((u32 *)data_page2) = MAGIC_VAL_2;
+	base_addr1 = (unsigned long)data_page1 & PAGE_MASK_2M;
+	base_addr2 = (unsigned long)data_page2 & PAGE_MASK_2M;
+	if (setup_ept_range(pml4, base_addr1, base_addr1 + PAGE_SIZE_2M, 0, 0,
+			    EPT_WA | EPT_RA | EPT_EA) ||
+	    setup_ept_range(pml4, base_addr2, base_addr2 + PAGE_SIZE_2M, 0, 0,
+			    EPT_WA | EPT_RA | EPT_EA))
+		init_fail = true;
 	install_ept(pml4, (unsigned long)data_page1, (unsigned long)data_page2,
 			EPT_RA | EPT_WA | EPT_EA);
 }
-- 
1.8.1.1.298.ge7eed54