Hi,
I am running QEMU in TCG mode (my server doesn't have kvm support), and I
am getting the memory traces in a x86 guest machine of all memory accesses,
including the PCID (process-context identifier, and I need that for my
current research), on a linux host. I have seen the TCG PCID feature flag
is commented out in target/i386/cpu.c, and if I directly emulate a CPU
which has PCID flag I got the warning:
warning: TCG doesn't support requested feature: CPUID.01H:ECX.pcid [bit 17]
so I uncommented the CPUID_EXT_PCID in TCG_EXT_FEATURES, and
the CPUID_7_0_EBX_INVPCID in TCG_7_0_EBX_FEATURES, in target/i386/cpu.c. I
have seen the PCID in the cr3 register in cpu get set, my question is that
I am not sure if there will be any issues with this flag. Why is it
commented out by default?
Just in case, I will put my commands here. Here are my configurations for
compiling:
*./configure --prefix=/tigress/kaifengx/sysroot/
--target-list=x86_64-softmmu,x86_64-linux-user --disable-kvm --disable-vnc
--enable-gtk --enable-plugins*
And my command for running the QEMU:
*qemu-system-x86_64 \*
* -cpu qemu64,+pcid\ -m 4G \ -icount shift=0 \ -drive
if=virtio,file=${DISK},cache=none \ -device pqii \ -trace
events=`pwd`/events \ -D ${LOG_FILE} \ -net
user,hostfwd=tcp::10022-:22 \ -net nic \ -display none \
-nographic \ -plugin QEMU_PATH/tests/plugin/libtlb.so,arg=inline,arg=io*
Best,
Kaifeng
