Commit c078ca96 authored by Luwei Kang's avatar Luwei Kang Committed by Eduardo Habkost
Browse files

i386: Disable Intel PT if packets IP payloads have LIP values 



Intel processor trace should be disabled when
CPUID.(EAX=14H,ECX=0H).ECX.[bit31] is set.
Generated packets which contain IP payloads will have LIP
values when this bit is set, or IP payloads will have RIP
values.
Currently, The information of CPUID 14H is constant to make
live migration safty and this bit is always 0 in guest even
if host support LIP values.
Guest sees the bit is 0 will expect IP payloads with RIP
values, but the host CPU will generate IP payloads with
LIP values if this bit is set in HW.
To make sure the value of IP payloads correctly, Intel PT
should be disabled when bit[31] is set.

Signed-off-by: default avatarLuwei Kang <luwei.kang@intel.com>
Message-Id: <1520969191-18162-1-git-send-email-luwei.kang@intel.com>
Signed-off-by: default avatarEduardo Habkost <ehabkost@redhat.com>
parent 99193d8f

target/i386/cpu.c

+4 −1
Original line number Diff line number Diff line
@@ -195,6 +195,8 @@ 
 * bit[02]: Support Single-Range Output scheme;

 */

#define INTEL_PT_MINIMAL_ECX     0x7

/* generated packets which contain IP payloads have LIP values */

#define INTEL_PT_IP_LIP          (1 << 31)

#define INTEL_PT_ADDR_RANGES_NUM 0x2 /* Number of configurable address ranges */

#define INTEL_PT_ADDR_RANGES_NUM_MASK 0x3

#define INTEL_PT_MTC_BITMAP      (0x0249 << 16) /* Support ART(0,3,6,9) */
@@ -4167,7 +4169,8 @@ static int x86_cpu_filter_features(X86CPU *cpu) 
           ((eax_1 & INTEL_PT_ADDR_RANGES_NUM_MASK) <

                                           INTEL_PT_ADDR_RANGES_NUM) ||

           ((ebx_1 & (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) !=

                (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP))) {

                (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) ||

           (ecx_0 & INTEL_PT_IP_LIP)) {

            /*

             * Processor Trace capabilities aren't configurable, so if the

             * host can't emulate the capabilities we report on