[PATCH v2 9/9] KVM: vmx: vmx instructions handling does not consider cs.l

Nadav Amit
2014-06-18T14:19:26Z

VMX instructions use 32-bit operands in 32-bit mode, and 64-bit operands in
64-bit mode. The current implementation is broken since it does not use the
register operands correctly, and always uses 64-bit for reads and writes.
Moreover, write to memory in vmwrite only considers long-mode, so it ignores
cs.l. This patch fixes this behavior. The field of vmread/vmwrite is kept
intentionally as 64-bit read since if bits [63:32] are not cleared the
instruction should fail, according to Intel SDM.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
---
arch/x86/kvm/vmx.c | 8 ++++----
arch/x86/kvm/x86.h | 9 +++++++++
2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index cbfbb8b..75dc888 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6397,7 +6397,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
* on the guest's mode (32 or 64 bit), not on the given field's length.
*/
if (vmx_instruction_info & (1u << 10)) {
- kvm_register_write(vcpu, (((vmx_instruction_info) >> 3) & 0xf),
+ kvm_register_writel(vcpu, (((vmx_instruction_info) >> 3) & 0xf),
field_value);
} else {
if (get_vmx_mem_address(vcpu, exit_qualification,
@@ -6434,14 +6434,14 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
return 1;

if (vmx_instruction_info & (1u << 10))
- field_value = kvm_register_read(vcpu,
+ field_value = kvm_register_readl(vcpu,
(((vmx_instruction_info) >> 3) & 0xf));
else {
if (get_vmx_mem_address(vcpu, exit_qualification,
vmx_instruction_info, &gva))
return 1;
if (kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, gva,
- &field_value, (is_long_mode(vcpu) ? 8 : 4), &e)) {
+ &field_value, (is_64_bit_mode(vcpu) ? 8 : 4), &e)) {
kvm_inject_page_fault(vcpu, &e);
return 1;
}
@@ -6571,7 +6571,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
}

vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
- type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);
+ type = kvm_register_readl(vcpu, (vmx_instruction_info >> 28) & 0xf);

types = (nested_vmx_ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6;

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index c5b61a7..306a1b7 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -126,6 +126,15 @@ static inline unsigned long kvm_register_readl(struct kvm_vcpu *vcpu,
return is_64_bit_mode(vcpu) ? val : (u32)val;
}

+static inline void kvm_register_writel(struct kvm_vcpu *vcpu,
+ enum kvm_reg reg,
+ unsigned long val)
+{
+ if (!is_64_bit_mode(vcpu))
+ val = (u32)val;
+ return kvm_register_write(vcpu, reg, val);
+}
+
void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
--
1.9.1