Hi Keir,
I saw you were committing some changes to my patch:
- if ( hvm_long_mode_enabled(v) )
- HVMTRACE_ND (VMEXIT64, 1/*cycles*/, v, 3, exit_reason,
- regs->eip & 0xFFFFFFFF, regs->eip >> 32, 0, 0, 0);
- else
- HVMTRACE_ND (VMEXIT, 1/*cycles*/, v, 2, exit_reason,
- regs->eip, 0, 0, 0, 0);
+ HVMTRACE_ND(VMEXIT64, 1/*cycles*/, v, 3, exit_reason,
+ (uint32_t)regs->eip, (uint32_t)((uint64_t)regs->eip >> 32),
+ 0, 0, 0);
This basically will always log 64bit values for the instruction pointer.
I thought about this approach, too, but didn't do it because I got the
impression that trace files are large enough and with the recently
introduced 'variable number of parameters' saving disk space is a concern.
Do you want to promote other pointers to always 64bit, too? Shall I
prepare a patch for this?
I also had the idea to include gzipping in the xentrace tool, this
should save about 80% of disk space at the cost of a slightly higher
Dom0 load (or use lzo?). Is this something I should implement?
Regards,
Andre
Andre Przywara wrote:
Hi,
Xen tracing some times ago used to put values of type 'long' into the
trace buffer. This has changed to uint32_t. Some trace points log
virtual addresses, which get cropped to 32bit in this case. There were
some inline functions to handle at least PF_XEN and VMEXIT, which caused
a lot of code duplication. The attached patch fixes several issues:
1. fix and extend tools/xentrace/formats
2. Fix xentrace_format to handle up to 7 parameters
3. create convenience macros to properly log long values
4. remove the inline functions in hvm/trace.h and replace them by macros
5. Change the CPUID trace to work correctly
6. group HVM trace points enable mechanism
I used a similar approach as in PV tracing with bit 8 indicating 64bit
pointers.
Discussion welcome!
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
BTW: Why is xentrace_format so awfully slow? I have rewritten the tool
in C and reached a speedup of more than 20 times. If someone bugs me I
will share the code...
Regards,
Andre.
--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 277-84917
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