On 09/21/2009 06:33 PM, Mohammed Gamal wrote:
With emulate_invalid_guest_state=1 Windows XP exits with an invalid guest state
due to rflags not being in a VMX-compliant state. This patch fixes this issue,
although Windows XP doesn't boot yet with invalid state emulation on.
Also added GDT and IDT checks while we're at it.
Signed-off-by: Mohammed Gamal<m.gamal005@xxxxxxxxx>
---
arch/x86/kvm/vmx.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 56 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3fe0d42..eaec4a5 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2022,6 +2022,23 @@ static bool ldtr_valid(struct kvm_vcpu *vcpu)
return true;
}
+static bool gdtr_idtr_valid(struct kvm_vcpu *vcpu)
+{
+ struct descriptor_table gdt;
+ struct descriptor_table idt;
+
+ vmx_get_gdt(vcpu,&gdt);
+ vmx_get_idt(vcpu,&idt);
+
+ if (gdt.limit& 0xffff0000)
+ return false;
+
+ if (idt.limit& 0xffff0000)
+ return false;
+
+ return true;
+}
gdt and idt limits cannot be > 0xffff, since the intstructions to load
them always use a 16 bit quantity.
+
static bool cs_ss_rpl_check(struct kvm_vcpu *vcpu)
{
struct kvm_segment cs, ss;
@@ -2033,6 +2050,41 @@ static bool cs_ss_rpl_check(struct kvm_vcpu *vcpu)
(ss.selector& SELECTOR_RPL_MASK));
}
+static bool rflags_valid(struct kvm_vcpu *vcpu)
+{
+ unsigned long rflags;
+ u32 entry_intr_info;
+
+ rflags = vmcs_readl(GUEST_RFLAGS);
+ entry_intr_info = vmcs_read32(VM_ENTRY_INTR_INFO_FIELD);
+#ifdef CONFIG_X86_64
+ if (rflags& 0xffffffffffc00000)
+ return false;
+ if (is_long_mode(vcpu))
+ if (rflags& X86_EFLAGS_VM)
+ return false;
+#else
+ if (rflags& 0xffc00000)
+ return false;
+#endif
+ if (rflags& 0x8000)
+ return false;
+ if (rflags& 0x20)
+ return false;
+ if (rflags& 0x8)
+ return false;
+ if (!(rflags& 0x2))
+ return false;
+
+ if ((entry_intr_info& INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_EXT_INTR
+ && (entry_intr_info& INTR_INFO_VALID_MASK)) {
+ if (!(rflags& X86_EFLAGS_IF))
+ return false;
+ }
+
+ return true;
+}
It's really difficult to tell what you are doing here since you're using
numbers instead of symbolic constants. But I think some of these are
generally illegal. !guest_state_valid() means "the state is valid for
x86 but not valid for vmx entry"; if it's generally invalid all bets are
off.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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