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| author | Suraj Jitindar Singh <sjitindarsingh@gmail.com> | 2019-07-03 03:20:21 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-07-15 04:41:26 +0200 |
| commit | 28d2a6e6684d9851905f379816d8a4d03587ed94 (patch) | |
| tree | da6632fc1ab2cbafe3c4d695d7a68422173e2a96 /arch/powerpc/include | |
| parent | KVM: PPC: Book3S HV: Always save guest pmu for guest capable of nesting (diff) | |
| download | linux-28d2a6e6684d9851905f379816d8a4d03587ed94.tar.xz linux-28d2a6e6684d9851905f379816d8a4d03587ed94.zip | |
powerpc/pmu: Set pmcregs_in_use in paca when running as LPAR
The ability to run nested guests under KVM means that a guest can also
act as a hypervisor for it's own nested guest. Currently
ppc_set_pmu_inuse() assumes that either FW_FEATURE_LPAR is set,
indicating a guest environment, and so sets the pmcregs_in_use flag in
the lppaca, or that it isn't set, indicating a hypervisor environment,
and so sets the pmcregs_in_use flag in the paca.
The pmcregs_in_use flag in the lppaca is used to communicate this
information to a hypervisor and so must be set in a guest environment.
The pmcregs_in_use flag in the paca is used by KVM code to determine
whether the host state of the performance monitoring unit (PMU) must
be saved and restored when running a guest.
Thus when a guest also acts as a hypervisor it must set this bit in
both places since it needs to ensure both that the real hypervisor
saves it's PMU registers when it runs (requires pmcregs_in_use flag in
lppaca), and that it saves it's own PMU registers when running a
nested guest (requires pmcregs_in_use flag in paca).
Modify ppc_set_pmu_inuse() so that the pmcregs_in_use bit is set in
both the lppaca and the paca when a guest (LPAR) is running with the
capability of running it's own guests (CONFIG_KVM_BOOK3S_HV_POSSIBLE).
Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190703012022.15644-2-sjitindarsingh@gmail.com
Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/include/asm/pmc.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/pmc.h b/arch/powerpc/include/asm/pmc.h index dc9a1ca70edf..c6bbe9778d3c 100644 --- a/arch/powerpc/include/asm/pmc.h +++ b/arch/powerpc/include/asm/pmc.h @@ -27,11 +27,10 @@ static inline void ppc_set_pmu_inuse(int inuse) #ifdef CONFIG_PPC_PSERIES get_lppaca()->pmcregs_in_use = inuse; #endif - } else { + } #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - get_paca()->pmcregs_in_use = inuse; + get_paca()->pmcregs_in_use = inuse; #endif - } #endif } |