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| author | Benjamin Herrenschmidt | 2018-01-12 03:37:16 +0100 |
|---|---|---|
| committer | Paul Mackerras | 2018-01-19 02:10:21 +0100 |
| commit | 9b9b13a6d1537ddc4caccd6f1c41b78edbc08437 (patch) | |
| tree | 6f276be60ff3f994a9c2bd47b1ff2afcbc734586 /arch/powerpc/kvm/book3s_hv_rmhandlers.S | |
| parent | KVM: PPC: Book3S HV: Make xive_pushed a byte, not a word (diff) | |
| download | kernel-qcow2-linux-9b9b13a6d1537ddc4caccd6f1c41b78edbc08437.tar.gz kernel-qcow2-linux-9b9b13a6d1537ddc4caccd6f1c41b78edbc08437.tar.xz kernel-qcow2-linux-9b9b13a6d1537ddc4caccd6f1c41b78edbc08437.zip | |
KVM: PPC: Book3S HV: Keep XIVE escalation interrupt masked unless ceded
This works on top of the single escalation support. When in single
escalation, with this change, we will keep the escalation interrupt
disabled unless the VCPU is in H_CEDE (idle). In any other case, we
know the VCPU will be rescheduled and thus there is no need to take
escalation interrupts in the host whenever a guest interrupt fires.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_rmhandlers.S')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 62 |
1 files changed, 61 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index a7f429bc6de0..a7a20b85d8eb 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1045,6 +1045,41 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) */ li r0,0 stb r0, VCPU_IRQ_PENDING(r4) + + /* + * In single escalation mode, if the escalation interrupt is + * on, we mask it. + */ + lbz r0, VCPU_XIVE_ESC_ON(r4) + cmpwi r0,0 + beq 1f + ld r10, VCPU_XIVE_ESC_RADDR(r4) + li r9, XIVE_ESB_SET_PQ_01 + ldcix r0, r10, r9 + sync + + /* We have a possible subtle race here: The escalation interrupt might + * have fired and be on its way to the host queue while we mask it, + * and if we unmask it early enough (re-cede right away), there is + * a theorical possibility that it fires again, thus landing in the + * target queue more than once which is a big no-no. + * + * Fortunately, solving this is rather easy. If the above load setting + * PQ to 01 returns a previous value where P is set, then we know the + * escalation interrupt is somewhere on its way to the host. In that + * case we simply don't clear the xive_esc_on flag below. It will be + * eventually cleared by the handler for the escalation interrupt. + * + * Then, when doing a cede, we check that flag again before re-enabling + * the escalation interrupt, and if set, we abort the cede. + */ + andi. r0, r0, XIVE_ESB_VAL_P + bne- 1f + + /* Now P is 0, we can clear the flag */ + li r0, 0 + stb r0, VCPU_XIVE_ESC_ON(r4) +1: no_xive: #endif /* CONFIG_KVM_XICS */ @@ -2756,7 +2791,32 @@ kvm_cede_prodded: /* we've ceded but we want to give control to the host */ kvm_cede_exit: ld r9, HSTATE_KVM_VCPU(r13) - b guest_exit_cont +#ifdef CONFIG_KVM_XICS + /* Abort if we still have a pending escalation */ + lbz r5, VCPU_XIVE_ESC_ON(r9) + cmpwi r5, 0 + beq 1f + li r0, 0 + stb r0, VCPU_CEDED(r9) +1: /* Enable XIVE escalation */ + li r5, XIVE_ESB_SET_PQ_00 + mfmsr r0 + andi. r0, r0, MSR_DR /* in real mode? */ + beq 1f + ld r10, VCPU_XIVE_ESC_VADDR(r9) + cmpdi r10, 0 + beq 3f + ldx r0, r10, r5 + b 2f +1: ld r10, VCPU_XIVE_ESC_RADDR(r9) + cmpdi r10, 0 + beq 3f + ldcix r0, r10, r5 +2: sync + li r0, 1 + stb r0, VCPU_XIVE_ESC_ON(r9) +#endif /* CONFIG_KVM_XICS */ +3: b guest_exit_cont /* Try to handle a machine check in real mode */ machine_check_realmode: |