0522604b09
VCPU TSC is not cleared by a warm reset (*), which leaves some types of Linux
guests (non-pvops guests and those with the kernel parameter no-kvmclock set)
vulnerable to the overflow in cyc2ns_offset fixed by upstream commit
9993bc635d01a6ee7f6b833b4ee65ce7c06350b1 ("sched/x86: Fix overflow in
cyc2ns_offset").
To put it in a nutshell, if such a Linux guest without the patch above applied
has been up more than 208 days and attempts a warm reset chances are that
the newly booted kernel will panic or hang.
(*) Intel Xeon E5 processors show the same broken behavior due to
the errata "TSC is Not Affected by Warm Reset" (Intel® Xeon®
Processor E5 Family Specification Update - August 2013): "The
TSC (Time Stamp Counter MSR 10H) should be cleared on
reset. Due to this erratum the TSC is not affected by warm
reset."
Cc: Will Auld <will.auld@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fernando Luis Vázquez Cao <fernando_b1@lab.ntt.co.jp>
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| .. | ||
| arch_dump.c | ||
| arch_memory_mapping.c | ||
| cc_helper_template.h | ||
| cc_helper.c | ||
| cpu-qom.h | ||
| cpu.c | ||
| cpu.h | ||
| excp_helper.c | ||
| fpu_helper.c | ||
| gdbstub.c | ||
| helper.c | ||
| helper.h | ||
| int_helper.c | ||
| ioport-user.c | ||
| kvm_i386.h | ||
| kvm-stub.c | ||
| kvm.c | ||
| machine.c | ||
| Makefile.objs | ||
| mem_helper.c | ||
| misc_helper.c | ||
| ops_sse_header.h | ||
| ops_sse.h | ||
| seg_helper.c | ||
| shift_helper_template.h | ||
| smm_helper.c | ||
| svm_helper.c | ||
| svm.h | ||
| TODO | ||
| topology.h | ||
| translate.c | ||