According to section "Checks on VMX Controls" in Intel SDM vol 3C, the
following checks performed for the VM-exit MSR-load address if the
the VM-exit MSR-load count field is non-zero:
- The lower 4 bits of the VM-exit MSR-load address must be 0.
The address should not set any bits beyond the processor’s
physical-address width.
- The address of the last byte in the VM-exit MSR-load area
should not set any bits beyond the processor’s physical-address
width. The address of this last byte is VM-exit MSR-load address
+ (MSR count * 16) - 1. (The arithmetic used for the computation
uses more bits than the processor’s physical-address width.)
If IA32_VMX_BASIC[48] is read as 1, neither address should set any bits
in the range 63:32.
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
Reviewed-by: Karl Heubaum <karl.heubaum@xxxxxxxxxx>
---
x86/vmx_tests.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index ee0c9ff..771b508 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -4804,6 +4804,75 @@ static void test_vmx_preemption_timer(void)
vmcs_write(EXI_CONTROLS, saved_exit);
}
+/*
+ * The following checks are performed for the VM-exit MSR-load address if
+ * the VM-exit MSR-load count field is non-zero:
+ *
+ * - The lower 4 bits of the VM-exit MSR-load address must be 0.
+ * The address should not set any bits beyond the processor’s
+ * physical-address width.
+ *
+ * - The address of the last byte in the VM-exit MSR-load area
+ * should not set any bits beyond the processor’s physical-address
+ * width. The address of this last byte is VM-exit MSR-load address
+ * + (MSR count * 16) - 1. (The arithmetic used for the computation
+ * uses more bits than the processor’s physical-address width.)
+ *
+ * If IA32_VMX_BASIC[48] is read as 1, neither address should set any bits
+ * in the range 63:32.
+ *
+ * [Intel SDM]
+ */
+static void test_exit_msr_load(void)
+{
+ exit_msr_load = alloc_page();
+ u64 tmp;
+ u32 exit_msr_ld_cnt = 1;
+ int i;
+ u32 addr_len = 64;
+
+ vmcs_write(EXI_MSR_LD_CNT, exit_msr_ld_cnt);
+
+ /* Check first 4 bits of VM-exit MSR-load address */
+ for (i = 0; i < 4; i++) {
+ tmp = (u64)exit_msr_load | 1ull << i;
+ vmcs_write(EXIT_MSR_LD_ADDR, tmp);
+ report_prefix_pushf("VM-exit MSR-load addr [4:0] %lx",
+ tmp & 0xf);
+ test_vmx_controls(false, false);
+ report_prefix_pop();
+ }
+
+ if (basic.val & (1ul << 48))
+ addr_len = 32;
+
+ test_vmcs_addr_values("VM-exit-MSR-load address",
+ EXIT_MSR_LD_ADDR, 16, false, false,
+ 4, addr_len - 1);
+
+ /*
+ * Check last byte of VM-exit MSR-load address
+ */
+ exit_msr_load = (struct vmx_msr_entry *)((u64)exit_msr_load & ~0xf);
+
+ for (i = (addr_len == 64 ? cpuid_maxphyaddr(): addr_len);
+ i < 64; i++) {
+ tmp = ((u64)exit_msr_load + exit_msr_ld_cnt * 16 - 1) |
+ 1ul << i;
+ vmcs_write(EXIT_MSR_LD_ADDR,
+ tmp - (exit_msr_ld_cnt * 16 - 1));
+ test_vmx_controls(false, false);
+ }
+
+ vmcs_write(EXI_MSR_LD_CNT, 2);
+ vmcs_write(EXIT_MSR_LD_ADDR, (1ULL << cpuid_maxphyaddr()) - 16);
+ test_vmx_controls(false, false);
+ vmcs_write(EXIT_MSR_LD_ADDR, (1ULL << cpuid_maxphyaddr()) - 32);
+ test_vmx_controls(true, false);
+ vmcs_write(EXIT_MSR_LD_ADDR, (1ULL << cpuid_maxphyaddr()) - 48);
+ test_vmx_controls(true, false);
+}
+
/*
* Tests for VM-execution control fields
*/
@@ -4907,6 +4976,7 @@ static void test_exit_msr_store(void)
static void test_vm_exit_ctls(void)
{
test_exit_msr_store();
+ test_exit_msr_load();
}
/*
--
2.17.2
