Reads of unbacked addresses from the PCI bus should return all
ones. Since kvm's VMCS revision identifier isn't 0xffffffff, this
means that a VMPTRLD with an argument outside of backed memory should
set the VM-instruction error number to 11 (VMPTRLD with incorrect VMCS
revision identifier) if there is already a valid VMCS pointer loaded.
make_vmcs_current() has been modified to return all of the arithmetic
flags, so that the caller can distinguish VMfailInvalid from
VMfailValid.
Suggested-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Reviewed-by: Peter Shier <pshier@xxxxxxxxxx>
---
x86/vmx.c | 17 ++++++++++++++---
x86/vmx.h | 10 ++++++----
2 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/x86/vmx.c b/x86/vmx.c
index 79a21d8..1318548 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -31,6 +31,7 @@
#include "libcflat.h"
#include "processor.h"
#include "alloc_page.h"
+#include "fwcfg.h"
#include "vm.h"
#include "desc.h"
#include "vmx.h"
@@ -1374,23 +1375,33 @@ static void test_vmptrld(void)
/* Unaligned page access */
tmp_root = (struct vmcs *)((intptr_t)vmcs + 1);
report("test vmptrld with unaligned vmcs",
- make_vmcs_current(tmp_root) == 1);
+ make_vmcs_current(tmp_root) == VM_FAIL_INVALID);
/* gpa bits beyond physical address width are set*/
tmp_root = (struct vmcs *)((intptr_t)vmcs |
((u64)1 << (width+1)));
report("test vmptrld with vmcs address bits set beyond physical address width",
- make_vmcs_current(tmp_root) == 1);
+ make_vmcs_current(tmp_root) == VM_FAIL_INVALID);
/* Pass VMXON region */
make_vmcs_current(vmcs);
tmp_root = (struct vmcs *)vmxon_region;
report("test vmptrld with vmxon region",
- make_vmcs_current(tmp_root) == 1);
+ make_vmcs_current(tmp_root) == VM_FAIL_VALID);
report("test vmptrld with vmxon region vm-instruction error",
vmcs_read(VMX_INST_ERROR) == VMXERR_VMPTRLD_VMXON_POINTER);
+ tmp_root = (struct vmcs *)(fwcfg_get_u64(FW_CFG_RAM_SIZE));
+ if ((uintptr_t)tmp_root < (1ul << width)) {
+ report("test vmptrld of unbacked physical address",
+ make_vmcs_current(tmp_root) == VM_FAIL_VALID);
+ report("test vmptrld of unbacked physical address vm-instruction error",
+ vmcs_read(VMX_INST_ERROR) ==
+ VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
+ }
+
report("test vmptrld with valid vmcs region", make_vmcs_current(vmcs) == 0);
+
}
static void test_vmptrst(void)
diff --git a/x86/vmx.h b/x86/vmx.h
index ba47455..6e3620b 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -7,6 +7,9 @@
#include "asm/page.h"
#include "asm/io.h"
+#define VM_FAIL_INVALID X86_EFLAGS_CF
+#define VM_FAIL_VALID X86_EFLAGS_ZF
+
struct vmcs_hdr {
u32 revision_id:31;
u32 shadow_vmcs:1;
@@ -680,12 +683,11 @@ static int vmx_off(void)
static inline int make_vmcs_current(struct vmcs *vmcs)
{
- bool ret;
u64 rflags = read_rflags() | X86_EFLAGS_CF | X86_EFLAGS_ZF;
- asm volatile ("push %1; popf; vmptrld %2; setbe %0"
- : "=q" (ret) : "q" (rflags), "m" (vmcs) : "cc");
- return ret;
+ asm volatile ("push %1; popf; vmptrld %2; pushf; pop %0"
+ : "=r" (rflags) : "0" (rflags), "m" (vmcs) : "cc");
+ return rflags & VMX_ENTRY_FLAGS;
}
static inline int vmcs_clear(struct vmcs *vmcs)
--
2.20.0.rc0.387.gc7a69e6b6c-goog
