Avi Kivity wrote:
> Jan Kiszka wrote:
>> Userland-located ROM memory is not available via kvm->physical_memory +
>> guest_address. To let kvm_show_code also dump useful information when
>> some problem in ROM (BIOS...) occurs, this patch first tries to obtain
>> the memory content via the mmio_read callback - maybe not 100% clean,
>> but works at least for the QEMU use case. If the callback complains
>> about the given address, we then fall back to RAM access.
>>
>>
>
> kvm->physical_memory is actually broken, since nothing guarantees a 1:1
> (+offset) mapping.
>
> Why not use ->mmio_read() all the time? Sure it overloads the
> definition of mmio_read(), but worse things have happened.
That was my first approach as well, but then I became unsure if such an
overloading is acceptable. As it is now:
----------
Userland-located memory is not unconditionally available via
kvm->physical_memory + guest_address. To let kvm_show_code also dump
useful information when, e.g., some problem in ROM (BIOS...) occurs,
this patch tries to obtain the memory content via the mmio_read
callback. If the callback fails, the code byte is marked as invalid.
This patch also removes the check for protected mode and dumps the code
in any case - I didn't find the reason for this restriction.
Signed-off-by: Jan Kiszka <[EMAIL PROTECTED]>
---
libkvm/libkvm-x86.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
Index: b/libkvm/libkvm-x86.c
===================================================================
--- a/libkvm/libkvm-x86.c
+++ b/libkvm/libkvm-x86.c
@@ -393,14 +393,14 @@ int kvm_set_pit(kvm_context_t kvm, struc
void kvm_show_code(kvm_context_t kvm, int vcpu)
{
-#define CR0_PE_MASK (1ULL<<0)
+#define SHOW_CODE_LEN 50
int fd = kvm->vcpu_fd[vcpu];
struct kvm_regs regs;
struct kvm_sregs sregs;
- int r;
- unsigned char code[50];
+ int r, n;
int back_offset;
- char code_str[sizeof(code) * 3 + 1];
+ unsigned char code;
+ char code_str[SHOW_CODE_LEN * 3 + 1];
unsigned long rip;
r = ioctl(fd, KVM_GET_SREGS, &sregs);
@@ -408,9 +408,6 @@ void kvm_show_code(kvm_context_t kvm, in
perror("KVM_GET_SREGS");
return;
}
- if (sregs.cr0 & CR0_PE_MASK)
- return;
-
r = ioctl(fd, KVM_GET_REGS, ®s);
if (r == -1) {
perror("KVM_GET_REGS");
@@ -420,12 +417,16 @@ void kvm_show_code(kvm_context_t kvm, in
back_offset = regs.rip;
if (back_offset > 20)
back_offset = 20;
- memcpy(code, kvm->physical_memory + rip - back_offset, sizeof code);
*code_str = 0;
- for (r = 0; r < sizeof code; ++r) {
- if (r == back_offset)
+ for (n = -back_offset; n < SHOW_CODE_LEN-back_offset; ++n) {
+ if (n == 0)
strcat(code_str, " -->");
- sprintf(code_str + strlen(code_str), " %02x", code[r]);
+ r = kvm->callbacks->mmio_read(kvm->opaque, rip + n, &code, 1);
+ if (r < 0) {
+ strcat(code_str, " xx");
+ continue;
+ }
+ sprintf(code_str + strlen(code_str), " %02x", code);
}
fprintf(stderr, "code:%s\n", code_str);
}
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