linux

iv/linux

History

Sean Christopherson 0b9ca98b72 perf/x86/core: Zero @lbr instead of returning -1 in x86_perf_get_lbr() stub

Drop the return value from x86_perf_get_lbr() and have the stub zero out
the @lbr structure instead of returning -1 to indicate "no LBR support".
KVM doesn't actually check the return value, and instead subtly relies on
zeroing the number of LBRs in intel_pmu_init().

Formalize "nr=0 means unsupported" so that KVM doesn't need to add a
pointless check on the return value to fix KVM's benign bug.

Note, the stub is necessary even though KVM x86 selects PERF_EVENTS and
the caller exists only when CONFIG_KVM_INTEL=y.  Despite the name,
KVM_INTEL doesn't strictly require CPU_SUP_INTEL, it can be built with
any of INTEL || CENTAUR || ZHAOXIN CPUs.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221006000314.73240-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2022-11-09 12:31:11 -05:00

amd

perf/mem: Rename PERF_MEM_LVLNUM_EXTN_MEM to PERF_MEM_LVLNUM_CXL

2022-10-27 10:27:32 +02:00

intel

perf/x86/core: Zero @lbr instead of returning -1 in x86_perf_get_lbr() stub

2022-11-09 12:31:11 -05:00

zhaoxin

x86: Fix various typos in comments

2021-03-18 15:31:53 +01:00

core.c

perf/x86/p4: Remove perfctr_second_write quirk