@@ -943,6 +943,18 @@ u64 virtual_vmcs_vmread(const struct vcpu *v, u32 vmcs_encoding)
return res;
}
+enum vmx_insn_errno virtual_vmcs_vmread_safe(const struct vcpu *v,
+ u32 vmcs_encoding, u64 *val)
+{
+ enum vmx_insn_errno ret;
+
+ virtual_vmcs_enter(v);
+ ret = vmread_safe(vmcs_encoding, val);
+ virtual_vmcs_exit(v);
+
+ return ret;
+}
+
void virtual_vmcs_vmwrite(const struct vcpu *v, u32 vmcs_encoding, u64 val)
{
virtual_vmcs_enter(v);
@@ -264,6 +264,25 @@ u64 get_vvmcs_real(const struct vcpu *v, u32 encoding)
return virtual_vmcs_vmread(v, encoding);
}
+enum vmx_insn_errno get_vvmcs_virtual_safe(void *vvmcs, u32 encoding, u64 *val)
+{
+ *val = get_vvmcs_virtual(vvmcs, encoding);
+
+ /*
+ * TODO: This should not always succeed. Fields and values need to be
+ * audited against the features offered to the guest in the VT-x MSRs.
+ * This should be fixed when the MSR levelling work is started, at which
+ * point there will be a cpuid_policy-like object.
+ */
+ return VMX_INSN_SUCCEED;
+}
+
+enum vmx_insn_errno get_vvmcs_real_safe(const struct vcpu *v, u32 encoding,
+ u64 *val)
+{
+ return virtual_vmcs_vmread_safe(v, encoding, val);
+}
+
void set_vvmcs_virtual(void *vvmcs, u32 vmcs_encoding, u64 val)
{
union vmcs_encoding enc;
@@ -1733,7 +1752,12 @@ int nvmx_handle_vmread(struct cpu_user_regs *regs)
if ( rc != X86EMUL_OKAY )
return rc;
- value = get_vvmcs(v, reg_read(regs, decode.reg2));
+ rc = get_vvmcs_safe(v, reg_read(regs, decode.reg2), &value);
+ if ( rc != VMX_INSN_SUCCEED )
+ {
+ vmfail(regs, rc);
+ return X86EMUL_OKAY;
+ }
switch ( decode.type ) {
case VMX_INST_MEMREG_TYPE_MEMORY:
@@ -538,6 +538,8 @@ int vmx_check_msr_bitmap(unsigned long *msr_bitmap, u32 msr, int access_type);
void virtual_vmcs_enter(const struct vcpu *);
void virtual_vmcs_exit(const struct vcpu *);
u64 virtual_vmcs_vmread(const struct vcpu *, u32 encoding);
+enum vmx_insn_errno virtual_vmcs_vmread_safe(const struct vcpu *v,
+ u32 vmcs_encoding, u64 *val);
void virtual_vmcs_vmwrite(const struct vcpu *, u32 encoding, u64 val);
enum vmx_insn_errno virtual_vmcs_vmwrite_safe(const struct vcpu *v,
u32 vmcs_encoding, u64 val);
@@ -183,6 +183,9 @@ u64 get_vvmcs_virtual(void *vvmcs, u32 encoding);
u64 get_vvmcs_real(const struct vcpu *, u32 encoding);
void set_vvmcs_virtual(void *vvmcs, u32 encoding, u64 val);
void set_vvmcs_real(const struct vcpu *, u32 encoding, u64 val);
+enum vmx_insn_errno get_vvmcs_virtual_safe(void *vvmcs, u32 encoding, u64 *val);
+enum vmx_insn_errno get_vvmcs_real_safe(const struct vcpu *, u32 encoding,
+ u64 *val);
enum vmx_insn_errno set_vvmcs_virtual_safe(void *vvmcs, u32 encoding, u64 val);
enum vmx_insn_errno set_vvmcs_real_safe(const struct vcpu *, u32 encoding,
u64 val);
@@ -197,6 +200,11 @@ enum vmx_insn_errno set_vvmcs_real_safe(const struct vcpu *, u32 encoding,
set_vvmcs_real(vcpu, encoding, val) : \
set_vvmcs_virtual(vcpu_nestedhvm(vcpu).nv_vvmcx, encoding, val))
+#define get_vvmcs_safe(vcpu, encoding, val) \
+ (cpu_has_vmx_vmcs_shadowing ? \
+ get_vvmcs_real_safe(vcpu, encoding, val) : \
+ get_vvmcs_virtual_safe(vcpu_nestedhvm(vcpu).nv_vvmcx, encoding, val))
+
#define set_vvmcs_safe(vcpu, encoding, val) \
(cpu_has_vmx_vmcs_shadowing ? \
set_vvmcs_real_safe(vcpu, encoding, val) : \
There is an issue with the original __vmread() in nested vmx mode: emulation of a guest's VMREAD with invalid arguments leads to BUG(). Fix this by using vmread_safe() and reporting any kind of VMfail back to the guest. A new safe versions of get_vvmcs() macro and related functions are introduced because of new function signatures and lots of existing users. Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com> --- v3 --> v4: * VMX_INSN_SUCCEED is used instead of 0 * added TODO comment into get_vvmcs_virtual_safe() based on Andrew's email xen/arch/x86/hvm/vmx/vmcs.c | 12 ++++++++++++ xen/arch/x86/hvm/vmx/vvmx.c | 26 +++++++++++++++++++++++++- xen/include/asm-x86/hvm/vmx/vmcs.h | 2 ++ xen/include/asm-x86/hvm/vmx/vvmx.h | 8 ++++++++ 4 files changed, 47 insertions(+), 1 deletion(-)