From: Gautham R. Shenoy Date: Fri, 7 Aug 2015 12:11:20 +0000 (+0530) Subject: KVM: PPC: Book3S HV: Exit on H_DOORBELL if HOST_IPI is set X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=06554d9f6cc8f0b5ec903db19726a15dfc7b09d6;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git KVM: PPC: Book3S HV: Exit on H_DOORBELL if HOST_IPI is set The code that handles the case when we receive a H_DOORBELL interrupt has a comment which says "Hypervisor doorbell - exit only if host IPI flag set". However, the current code does not actually check if the host IPI flag is set. This is due to a comparison instruction that got missed. As a result, the current code performs the exit to host only if some sibling thread or a sibling sub-core is exiting to the host. This implies that, an IPI sent to a sibling core in (subcores-per-core != 1) mode will be missed by the host unless the sibling core is on the exit path to the host. This patch adds the missing comparison operation which will ensure that when HOST_IPI flag is set, we unconditionally exit to the host. Fixes: 66feed61cdf6 Cc: stable@vger.kernel.org # v4.1+ Signed-off-by: Gautham R. Shenoy Reviewed-by: David Gibson Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index b07f04550969..2273dcacef39 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1213,6 +1213,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) cmpwi r12, BOOK3S_INTERRUPT_H_DOORBELL bne 3f lbz r0, HSTATE_HOST_IPI(r13) + cmpwi r0, 0 beq 4f b guest_exit_cont 3: