From: Suraj Jitindar Singh sjitindarsingh@gmail.com
commit 28d2a6e6684d9851905f379816d8a4d03587ed94 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/include/asm/pmc.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- 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 #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 }