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KVM: Support mixed endian machines

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Currently kvmtrace is not portable. This will prevent from copying a
trace file from big-endian target to little-endian workstation for analysis.
In the patch, kernel outputs metadata containing a magic number to trace
log, and changes 64-bit words to be u64 instead of a pair of u32s.

Signed-off-by: Tan Li <li.tan@intel.com>
Acked-by: Jerone Young <jyoung5@us.ibm.com>
Acked-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Tan, Li 2008-05-23 14:54:09 +08:00 committed by Avi Kivity
parent 25be46080f
commit 9ef621d3be
2 changed files with 14 additions and 8 deletions
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4
include/linux/kvm.h
View File

@ -318,14 +318,14 @@ struct kvm_trace_rec {
__u32 vcpu_id;
union {
struct {
__u32 cycle_lo, cycle_hi;
__u64 cycle_u64;
__u32 extra_u32[KVM_TRC_EXTRA_MAX];
} cycle;
struct {
__u32 extra_u32[KVM_TRC_EXTRA_MAX];
} nocycle;
} u;
};
} __attribute__((packed));
#define KVMIO 0xAE

18
virt/kvm/kvm_trace.c
View File

@ -72,11 +72,7 @@ static void kvm_add_trace(void *probe_private, void *call_data,
rec.cycle_in = p->cycle_in;
if (rec.cycle_in) {
u64 cycle = 0;
cycle = get_cycles();
rec.u.cycle.cycle_lo = (u32)cycle;
rec.u.cycle.cycle_hi = (u32)(cycle >> 32);
rec.u.cycle.cycle_u64 = get_cycles();
for (i = 0; i < rec.extra_u32; i++)
rec.u.cycle.extra_u32[i] = va_arg(*args, u32);
@ -114,8 +110,18 @@ static int kvm_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
{
struct kvm_trace *kt;
if (!relay_buf_full(buf))
if (!relay_buf_full(buf)) {
if (!prev_subbuf) {
/*
* executed only once when the channel is opened
* save metadata as first record
*/
subbuf_start_reserve(buf, sizeof(u32));
*(u32 *)subbuf = 0x12345678;
}
return 1;
}
kt = buf->chan->private_data;
atomic_inc(&kt->lost_records);