kvm: Fix protected mode code dump

This patch fixes protected mode code dump not to take 16-bit segment selector
into account when calculating the guest flat address.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index 6f43cd33171d8692613e535d7f751a25cbd84d6b..e22c46eeb51117dc068a5ce83e871efbbb9dd6f4 100644 (file)
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -296,9 +296,18 @@ static inline uint64_t ip_flat_to_real(struct kvm *self, uint64_t ip)
        return ip - (cs << 4);
 }
 
-static inline uint64_t ip_real_to_flat(struct kvm *self, uint64_t ip)
+static inline uint64_t ip_to_flat(struct kvm *self, uint64_t ip)
 {
-       uint64_t cs = self->sregs.cs.selector;
+       uint64_t cs;
+
+       /*
+        * NOTE! We should take code segment base address into account here.
+        * Luckily it's usually zero because Linux uses flat memory model.
+        */
+       if (self->sregs.cr0 & 0x01)
+               return ip;
+
+       cs = self->sregs.cs.selector;
 
        return ip + (cs << 4);
 }
@@ -505,14 +514,14 @@ void kvm__show_code(struct kvm *self)
        if (ioctl(self->vcpu_fd, KVM_GET_SREGS, &self->sregs) < 0)
                die("KVM_GET_SREGS failed");
 
-       ip = guest_flat_to_host(self, ip_real_to_flat(self, self->regs.rip) - code_prologue);
+       ip = guest_flat_to_host(self, ip_to_flat(self, self->regs.rip) - code_prologue);
 
        printf("Code: ");
 
        for (i = 0; i < code_len; i++, ip++) {
                c = *ip;
 
-               if (ip == guest_flat_to_host(self, ip_real_to_flat(self, self->regs.rip)))
+               if (ip == guest_flat_to_host(self, ip_to_flat(self, self->regs.rip)))
                        printf("<%02x> ", c);
                else
                        printf("%02x ", c);