On Wed, Jun 18, 2014 at 03:52:55PM +0000, Liang, Kan wrote: > perf ignore LBR and offcore_rsp. > > x86, perf: Protect LBR and offcore rsp against KVM lying > > With -cpu host, KVM reports LBR and offcore support, if the host has support. > When the guest perf driver tries to access LBR or offcore_rsp MSR, > it #GPs all MSR accesses,since KVM doesn't handle LBR and offcore support. > So LBR and offcore rsp MSRs are needed to be protected by _safe(). > > For reproducing the issue, please build the kernel with CONFIG_KVM_INTEL = y. > And CONFIG_PARAVIRT = n and CONFIG_KVM_GUEST = n. > Start the guest with -cpu host. > Run perf record with --branch-any or --branch-filter in guest to trigger LBR #GP. > Run perf stat offcore events (E.g. LLC-loads/LLC-load-misses ...) in guest to trigger offcore_rsp #GP > > Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> This order indicates Andi is the author; but there's no corresponding From. > Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx> And here I thought that Andi was of the opinion that if you set CPUID to indicate a particular CPU you had better also handle all its MSRs.
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