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Maciej S. Szmigiero 3f2a05b31e target/i386: Reset TSCs of parked vCPUs too on VM reset ... Since commit 5286c36622 ("target/i386: properly reset TSC on reset") QEMU writes the special value of "1" to each online vCPU TSC on VM reset to reset it. However parked vCPUs don't get that handling and due to that their TSCs get desynchronized when the VM gets reset. This in turn causes KVM to turn off PVCLOCK_TSC_STABLE_BIT in its exported PV clock. Note that KVM has no understanding of vCPU being currently parked. Without PVCLOCK_TSC_STABLE_BIT the sched clock is marked unstable in the guest's kvm_sched_clock_init(). This causes a performance regressions to show in some tests. Fix this issue by writing the special value of "1" also to TSCs of parked vCPUs on VM reset. Reproducing the issue: 1) Boot a VM with "-smp 2,maxcpus=3" or similar 2) device_add host-x86_64-cpu,id=vcpu,node-id=0,socket-id=0,core-id=2,thread-id=0 3) Wait a few seconds 4) device_del vcpu 5) Inside the VM run: # echo "t" >/proc/sysrq-trigger; dmesg | grep sched_clock_stable Observe the sched_clock_stable() value is 1. 6) Reboot the VM 7) Once the VM boots once again run inside it: # echo "t" >/proc/sysrq-trigger; dmesg | grep sched_clock_stable Observe the sched_clock_stable() value is now 0. Fixes: 5286c36622 ("target/i386: properly reset TSC on reset") Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Link: https://lore.kernel.org/r/5a605a88e9a231386dc803c60f5fed9b48108139.1734014926.git.maciej.szmigiero@oracle.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		1 month ago
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aarch64-bsd-user.mak	bsd-user: Add aarch64 build to tree	6 months ago
aarch64-linux-user.mak	linux-user,aarch64: move to syscalltbl file	4 months ago
aarch64-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
aarch64_be-linux-user.mak	config/targets: update aarch64_be-linux-user gdb XML list	3 months ago
alpha-linux-user.mak	target/alpha: Remove TARGET_ALIGNED_ONLY	2 years ago
alpha-softmmu.mak	target/alpha: Remove TARGET_ALIGNED_ONLY	2 years ago
arm-bsd-user.mak	bsd-user: add arm target build	3 years ago
arm-linux-user.mak	semihosting: Split out guestfd.c	3 years ago
arm-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
armeb-linux-user.mak	semihosting: Split out guestfd.c	3 years ago
avr-softmmu.mak	…
hexagon-linux-user.mak	linux-user,hexagon: move to syscalltbl file	4 months ago
hppa-linux-user.mak	target/hppa: Remove TARGET_HPPA64	1 year ago
hppa-softmmu.mak	target/hppa: Remove TARGET_ALIGNED_ONLY	2 years ago
i386-bsd-user.mak	…
i386-linux-user.mak	target/i386/gdbstub: Expose orig_ax	3 months ago
i386-softmmu.mak	target/i386: Reset TSCs of parked vCPUs too on VM reset	1 month ago
loongarch64-linux-user.mak	linux-user,loongarch: move to syscalltbl file	4 months ago
loongarch64-softmmu.mak	target/loongarch/gdbstub: Add vector registers support	6 months ago
m68k-linux-user.mak	Replace TARGET_WORDS_BIGENDIAN	3 years ago
m68k-softmmu.mak	Replace TARGET_WORDS_BIGENDIAN	3 years ago
microblaze-linux-user.mak	target/microblaze: Add gdbstub xml	2 years ago
microblaze-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
microblazeel-linux-user.mak	target/microblaze: Add gdbstub xml	2 years ago
microblazeel-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
mips-linux-user.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mips-softmmu.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mips64-linux-user.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mips64-softmmu.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mips64el-linux-user.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mips64el-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
mipsel-linux-user.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mipsel-softmmu.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mipsn32-linux-user.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
mipsn32el-linux-user.mak	target/mips: Remove TARGET_ALIGNED_ONLY	2 years ago
or1k-linux-user.mak	linux-user,openrisc: move to syscalltbl file	4 months ago
or1k-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
ppc-linux-user.mak	Replace TARGET_WORDS_BIGENDIAN	3 years ago
ppc-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
ppc64-linux-user.mak	Replace TARGET_WORDS_BIGENDIAN	3 years ago
ppc64-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
ppc64le-linux-user.mak	…
riscv32-linux-user.mak	linux-user,riscv: move to syscalltbl file	4 months ago
riscv32-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
riscv64-bsd-user.mak	bsd-user: Add RISC-V 64-bit Target Configuration and Debug XML Files	4 months ago
riscv64-linux-user.mak	linux-user,riscv: move to syscalltbl file	4 months ago
riscv64-softmmu.mak	target/riscv: Enable RV32 CPU support in RV64 QEMU	3 months ago
rx-softmmu.mak	configs: disable emulators that require it if libfdt is not found	9 months ago
s390x-linux-user.mak	s390x/gdb: Split s390-virt.xml	2 years ago
s390x-softmmu.mak	kvm: use configs/ definition to conditionalize debug support	9 months ago
sh4-linux-user.mak	target/sh4: Remove TARGET_ALIGNED_ONLY	2 years ago
sh4-softmmu.mak	target/sh4: Remove TARGET_ALIGNED_ONLY	2 years ago
sh4eb-linux-user.mak	target/sh4: Remove TARGET_ALIGNED_ONLY	2 years ago
sh4eb-softmmu.mak	Revert "Remove the unused sh4eb target"	3 months ago
sparc-linux-user.mak	target/sparc: Remove TARGET_ALIGNED_ONLY	2 years ago
sparc-softmmu.mak	configs: Enable MTTCG for sparc, sparc64	1 year ago
sparc32plus-linux-user.mak	target/sparc: Remove TARGET_ALIGNED_ONLY	2 years ago
sparc64-linux-user.mak	target/sparc: Remove TARGET_ALIGNED_ONLY	2 years ago
sparc64-softmmu.mak	configs: Enable MTTCG for sparc, sparc64	1 year ago
tricore-softmmu.mak	…
x86_64-bsd-user.mak	…
x86_64-linux-user.mak	target/i386/gdbstub: Expose orig_ax	3 months ago
x86_64-softmmu.mak	target/i386: Reset TSCs of parked vCPUs too on VM reset	1 month ago
xtensa-linux-user.mak	…
xtensa-softmmu.mak	…
xtensaeb-linux-user.mak	Replace TARGET_WORDS_BIGENDIAN	3 years ago
xtensaeb-softmmu.mak	Replace TARGET_WORDS_BIGENDIAN	3 years ago