[PATCH 1/2] kvm-unit-tests: VMX: The framework of EPT for nested VMX testing

Arthur Chunqi Li
2013-09-09T04:57:36Z

The framework of EPT for nested VMX, including functions to build up
EPT paging structures, read/set EPT PTEs and setup a range of 1:1 map
EPT.

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
---
x86/vmx.c | 159 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
x86/vmx.h | 76 +++++++++++++++++++++++++++++
2 files changed, 231 insertions(+), 4 deletions(-)

diff --git a/x86/vmx.c b/x86/vmx.c
index ca36d35..87d1d55 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -143,6 +143,159 @@ asm(
" call hypercall\n\t"
);

+/* EPT paging structure related functions */
+/* install_ept_entry : Install a page to a given level in EPT
+ @pml4 : addr of pml4 table
+ @pte_level : level of PTE to set
+ @guest_addr : physical address of guest
+ @pte : pte value to set
+ @pt_page : address of page table, NULL for a new page
+ */
+void install_ept_entry(unsigned long *pml4,
+ int pte_level,
+ unsigned long guest_addr,
+ unsigned long pte,
+ unsigned long *pt_page)
+{
+ int level;
+ unsigned long *pt = pml4;
+ unsigned offset;
+
+ for (level = EPT_PAGE_LEVEL; level > pte_level; --level) {
+ offset = (guest_addr >> ((level-1) * EPT_PGDIR_WIDTH + 12))
+ & EPT_PGDIR_MASK;
+ if (!(pt[offset] & (EPT_PRESENT))) {
+ unsigned long *new_pt = pt_page;
+ if (!new_pt)
+ new_pt = alloc_page();
+ else
+ pt_page = 0;
+ memset(new_pt, 0, PAGE_SIZE);
+ pt[offset] = virt_to_phys(new_pt)
+ | EPT_RA | EPT_WA | EPT_EA;
+ }
+ pt = phys_to_virt(pt[offset] & 0xffffffffff000ull);
+ }
+ offset = ((unsigned long)guest_addr >> ((level-1) *
+ EPT_PGDIR_WIDTH + 12)) & EPT_PGDIR_MASK;
+ pt[offset] = pte;
+}
+
+/* Map a page, @perm is the permission of the page */
+void install_ept(unsigned long *pml4,
+ unsigned long phys,
+ unsigned long guest_addr,
+ u64 perm)
+{
+ install_ept_entry(pml4, 1, guest_addr, (phys & PAGE_MASK) | perm, 0);
+}
+
+/* Map a 1G-size page */
+void install_1g_ept(unsigned long *pml4,
+ unsigned long phys,
+ unsigned long guest_addr,
+ u64 perm)
+{
+ install_ept_entry(pml4, 3, guest_addr,
+ (phys & PAGE_MASK) | perm | EPT_LARGE_PAGE, 0);
+}
+
+/* Map a 2M-size page */
+void install_2m_ept(unsigned long *pml4,
+ unsigned long phys,
+ unsigned long guest_addr,
+ u64 perm)
+{
+ install_ept_entry(pml4, 2, guest_addr,
+ (phys & PAGE_MASK) | perm | EPT_LARGE_PAGE, 0);
+}
+
+/* setup_ept_range : Setup a range of 1:1 mapped page to EPT paging structure.
+ @start : start address of guest page
+ @len : length of address to be mapped
+ @map_1g : whether 1G page map is used
+ @map_2m : whether 2M page map is used
+ @perm : permission for every page
+ */
+int setup_ept_range(unsigned long *pml4, unsigned long start,
+ unsigned long len, int map_1g, int map_2m, u64 perm)
+{
+ u64 phys = start;
+ u64 max = (u64)len + (u64)start;
+
+ if (map_1g) {
+ while (phys + PAGE_SIZE_1G <= max) {
+ install_1g_ept(pml4, phys, phys, perm);
+ phys += PAGE_SIZE_1G;
+ }
+ }
+ if (map_2m) {
+ while (phys + PAGE_SIZE_2M <= max) {
+ install_2m_ept(pml4, phys, phys, perm);
+ phys += PAGE_SIZE_2M;
+ }
+ }
+ while (phys + PAGE_SIZE <= max) {
+ install_ept(pml4, phys, phys, perm);
+ phys += PAGE_SIZE;
+ }
+ return 0;
+}
+
+/* get_ept_pte : Get the PTE of a given level in EPT,
+ @level == 1 means get the latest level*/
+unsigned long get_ept_pte(unsigned long *pml4,
+ unsigned long guest_addr, int level)
+{
+ int l;
+ unsigned long *pt = pml4, pte;
+ unsigned offset;
+
+ for (l = EPT_PAGE_LEVEL; l > 1; --l) {
+ offset = (guest_addr >> (((l-1) * EPT_PGDIR_WIDTH) + 12))
+ & EPT_PGDIR_MASK;
+ pte = pt[offset];
+ if (!(pte & (EPT_PRESENT)))
+ return 0;
+ if (l == level)
+ return pte;
+ if (l < 4 && (pte & EPT_LARGE_PAGE))
+ return pte;
+ pt = (unsigned long *)(pte & 0xffffffffff000ull);
+ }
+ offset = (guest_addr >> (((l-1) * EPT_PGDIR_WIDTH) + 12))
+ & EPT_PGDIR_MASK;
+ pte = pt[offset];
+ return pte;
+}
+
+int set_ept_pte(unsigned long *pml4, unsigned long guest_addr,
+ int level, u64 pte_val)
+{
+ int l;
+ unsigned long *pt = pml4;
+ unsigned offset;
+
+ if (level < 1 || level > 3)
+ return -1;
+ for (l = EPT_PAGE_LEVEL; l > 1; --l) {
+ offset = (guest_addr >> (((l-1) * EPT_PGDIR_WIDTH) + 12))
+ & EPT_PGDIR_MASK;
+ if (l == level) {
+ pt[offset] = pte_val;
+ return 0;
+ }
+ if (!(pt[offset] & (EPT_PRESENT)))
+ return -1;
+ pt = (unsigned long *)(pt[offset] & 0xffffffffff000ull);
+ }
+ offset = (guest_addr >> (((l-1) * EPT_PGDIR_WIDTH) + 12))
+ & EPT_PGDIR_MASK;
+ pt[offset] = pte_val;
+ return 0;
+}
+
+
static void init_vmcs_ctrl(void)
{
/* 26.2 CHECKS ON VMX CONTROLS AND HOST-STATE AREA */
@@ -336,10 +489,8 @@ static void init_vmx(void)
: MSR_IA32_VMX_ENTRY_CTLS);
ctrl_cpu_rev[0].val = rdmsr(basic.ctrl ? MSR_IA32_VMX_TRUE_PROC
: MSR_IA32_VMX_PROCBASED_CTLS);
- if (ctrl_cpu_rev[0].set & CPU_SECONDARY)
- ctrl_cpu_rev[1].val = rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2);
- if (ctrl_cpu_rev[1].set & CPU_EPT || ctrl_cpu_rev[1].set & CPU_VPID)
- ept_vpid.val = rdmsr(MSR_IA32_VMX_EPT_VPID_CAP);
+ ctrl_cpu_rev[1].val = rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2);
+ ept_vpid.val = rdmsr(MSR_IA32_VMX_EPT_VPID_CAP);

write_cr0((read_cr0() & fix_cr0_clr) | fix_cr0_set);
write_cr4((read_cr4() & fix_cr4_clr) | fix_cr4_set | X86_CR4_VMXE);
diff --git a/x86/vmx.h b/x86/vmx.h
index 28595d8..742c2b2 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -432,6 +432,59 @@ enum Ctrl1 {
#define HYPERCALL_MASK 0xFFF
#define HYPERCALL_VMEXIT 0x1

+#define EPTP_PG_WALK_LEN_SHIFT 3ul
+#define EPTP_AD_FLAG (1ul << 6)
+
+#define EPT_MEM_TYPE_UC 0ul
+#define EPT_MEM_TYPE_WC 1ul
+#define EPT_MEM_TYPE_WT 4ul
+#define EPT_MEM_TYPE_WP 5ul
+#define EPT_MEM_TYPE_WB 6ul
+
+#define EPT_RA 1ul
+#define EPT_WA 2ul
+#define EPT_EA 4ul
+#define EPT_PRESENT (EPT_RA | EPT_WA | EPT_EA)
+#define EPT_ACCESS_FLAG (1ul << 8)
+#define EPT_DIRTY_FLAG (1ul << 9)
+#define EPT_LARGE_PAGE (1ul << 7)
+#define EPT_MEM_TYPE_SHIFT 3ul
+#define EPT_IGNORE_PAT (1ul << 6)
+#define EPT_SUPPRESS_VE (1ull << 63)
+
+#define EPT_CAP_WT 1ull
+#define EPT_CAP_PWL4 (1ull << 6)
+#define EPT_CAP_UC (1ull << 8)
+#define EPT_CAP_WB (1ull << 14)
+#define EPT_CAP_2M_PAGE (1ull << 16)
+#define EPT_CAP_1G_PAGE (1ull << 17)
+#define EPT_CAP_INVEPT (1ull << 20)
+#define EPT_CAP_INVEPT_SINGLE (1ull << 25)
+#define EPT_CAP_INVEPT_ALL (1ull << 26)
+#define EPT_CAP_AD_FLAG (1ull << 21)
+
+#define PAGE_SIZE_2M (512 * PAGE_SIZE)
+#define PAGE_SIZE_1G (512 * PAGE_SIZE_2M)
+#define EPT_PAGE_LEVEL 4
+#define EPT_PGDIR_WIDTH 9
+#define EPT_PGDIR_MASK 511
+#define PAGE_MASK (~(PAGE_SIZE-1))
+
+#define EPT_VLT_RD 1
+#define EPT_VLT_WR (1 << 1)
+#define EPT_VLT_FETCH (1 << 2)
+#define EPT_VLT_PERM_RD (1 << 3)
+#define EPT_VLT_PERM_WR (1 << 4)
+#define EPT_VLT_PERM_EX (1 << 5)
+#define EPT_VLT_LADDR_VLD (1 << 7)
+#define EPT_VLT_PADDR (1 << 8)
+
+#define MAGIC_VAL_1 0x12345678ul
+#define MAGIC_VAL_2 0x87654321ul
+#define MAGIC_VAL_3 0xfffffffful
+
+#define INVEPT_SINGLE 1
+#define INVEPT_GLOBAL 2

extern struct regs regs;

@@ -472,8 +525,31 @@ static inline int vmcs_save(struct vmcs **vmcs)
return ret;
}

+static inline void invept(unsigned long type, u64 eptp)
+{
+ struct {
+ u64 eptp, gpa;
+ } operand = {eptp, 0};
+ asm volatile("invept %0, %1\n" ::"m"(operand),"r"(type));
+}
+
void report(const char *name, int result);
void print_vmexit_info();
+void install_ept_entry(unsigned long *pml4, int pte_level,
+ unsigned long guest_addr, unsigned long pte,
+ unsigned long *pt_page);
+void install_1g_ept(unsigned long *pml4, unsigned long phys,
+ unsigned long guest_addr, u64 perm);
+void install_2m_ept(unsigned long *pml4, unsigned long phys,
+ unsigned long guest_addr, u64 perm);
+void install_ept(unsigned long *pml4, unsigned long phys,
+ unsigned long guest_addr, u64 perm);
+int setup_ept_range(unsigned long *pml4, unsigned long start,
+ unsigned long len, int map_1g, int map_2m, u64 perm);
+unsigned long get_ept_pte(unsigned long *pml4,
+ unsigned long guest_addr, int level);
+int set_ept_pte(unsigned long *pml4, unsigned long guest_addr,
+ int level, u64 pte_val);

#endif

--
1.7.9.5