Dongli Zhang 0848767dee xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32 ... [ Upstream commit eed05744322da07dd7e419432dcedf3c2e017179 ] The sched_clock() can be used very early since commit 857baa87b6 ("sched/clock: Enable sched clock early"). In addition, with commit 38669ba205 ("x86/xen/time: Output xen sched_clock time from 0"), kdump kernel in Xen HVM guest may panic at very early stage when accessing &__this_cpu_read(xen_vcpu)->time as in below: setup_arch() -> init_hypervisor_platform() -> x86_init.hyper.init_platform = xen_hvm_guest_init() -> xen_hvm_init_time_ops() -> xen_clocksource_read() -> src = &__this_cpu_read(xen_vcpu)->time; This is because Xen HVM supports at most MAX_VIRT_CPUS=32 'vcpu_info' embedded inside 'shared_info' during early stage until xen_vcpu_setup() is used to allocate/relocate 'vcpu_info' for boot cpu at arbitrary address. However, when Xen HVM guest panic on vcpu >= 32, since xen_vcpu_info_reset(0) would set per_cpu(xen_vcpu, cpu) = NULL when vcpu >= 32, xen_clocksource_read() on vcpu >= 32 would panic. This patch calls xen_hvm_init_time_ops() again later in xen_hvm_smp_prepare_boot_cpu() after the 'vcpu_info' for boot vcpu is registered when the boot vcpu is >= 32. This issue can be reproduced on purpose via below command at the guest side when kdump/kexec is enabled: "taskset -c 33 echo c > /proc/sysrq-trigger" The bugfix for PVM is not implemented due to the lack of testing environment. [boris: xen_hvm_init_time_ops() returns on errors instead of jumping to end] Cc: Joe Jin <joe.jin@oracle.com> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20220302164032.14569-3-dongli.zhang@oracle.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-04-15 14:15:03 +02:00
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apic.c
debugfs.c
debugfs.h
efi.c
enlighten_hvm.c
enlighten_pv.c	xen/x86: fix PV trap handling on secondary processors	2021-10-06 15:31:10 +02:00
enlighten_pvh.c
enlighten.c
grant-table.c
irq.c
Kconfig
Makefile
mmu_hvm.c
mmu_pv.c
mmu.c
mmu.h
multicalls.c
multicalls.h
p2m.c
pci-swiotlb-xen.c
platform-pci-unplug.c
pmu.c	xen: fix is_xen_pmu()	2022-04-15 14:14:53 +02:00
pmu.h	xen: fix is_xen_pmu()	2022-04-15 14:14:53 +02:00
setup.c
smp_hvm.c	xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32	2022-04-15 14:15:03 +02:00
smp_pv.c	xen: fix is_xen_pmu()	2022-04-15 14:14:53 +02:00
smp.c
smp.h
spinlock.c
suspend_hvm.c
suspend_pv.c
suspend.c
time.c	xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32	2022-04-15 14:15:03 +02:00
trace.c
vdso.h
vga.c
xen-asm_32.S
xen-asm_64.S
xen-asm.S
xen-head.S
xen-ops.h
xen-pvh.S