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-rw-r--r--arch/powerpc/kvm/book3s_hv_rmhandlers.S60
1 files changed, 58 insertions, 2 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 07c8b5b0f9d2..974793435a2e 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -86,6 +86,12 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
lbz r4, LPPACA_PMCINUSE(r3)
cmpwi r4, 0
beq 23f /* skip if not */
+BEGIN_FTR_SECTION
+ ld r3, HSTATE_MMCR(r13)
+ andi. r4, r3, MMCR0_PMAO_SYNC | MMCR0_PMAO
+ cmpwi r4, MMCR0_PMAO
+ beql kvmppc_fix_pmao
+END_FTR_SECTION_IFSET(CPU_FTR_PMAO_BUG)
lwz r3, HSTATE_PMC(r13)
lwz r4, HSTATE_PMC + 4(r13)
lwz r5, HSTATE_PMC + 8(r13)
@@ -737,6 +743,12 @@ skip_tm:
sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
mtspr SPRN_MMCR0, r3 /* freeze all counters, disable ints */
isync
+BEGIN_FTR_SECTION
+ ld r3, VCPU_MMCR(r4)
+ andi. r5, r3, MMCR0_PMAO_SYNC | MMCR0_PMAO
+ cmpwi r5, MMCR0_PMAO
+ beql kvmppc_fix_pmao
+END_FTR_SECTION_IFSET(CPU_FTR_PMAO_BUG)
lwz r3, VCPU_PMC(r4) /* always load up guest PMU registers */
lwz r5, VCPU_PMC + 4(r4) /* to prevent information leak */
lwz r6, VCPU_PMC + 8(r4)
@@ -1439,6 +1451,30 @@ END_FTR_SECTION_IFCLR(CPU_FTR_TM)
25:
/* Save PMU registers if requested */
/* r8 and cr0.eq are live here */
+BEGIN_FTR_SECTION
+ /*
+ * POWER8 seems to have a hardware bug where setting
+ * MMCR0[PMAE] along with MMCR0[PMC1CE] and/or MMCR0[PMCjCE]
+ * when some counters are already negative doesn't seem
+ * to cause a performance monitor alert (and hence interrupt).
+ * The effect of this is that when saving the PMU state,
+ * if there is no PMU alert pending when we read MMCR0
+ * before freezing the counters, but one becomes pending
+ * before we read the counters, we lose it.
+ * To work around this, we need a way to freeze the counters
+ * before reading MMCR0. Normally, freezing the counters
+ * is done by writing MMCR0 (to set MMCR0[FC]) which
+ * unavoidably writes MMCR0[PMA0] as well. On POWER8,
+ * we can also freeze the counters using MMCR2, by writing
+ * 1s to all the counter freeze condition bits (there are
+ * 9 bits each for 6 counters).
+ */
+ li r3, -1 /* set all freeze bits */
+ clrrdi r3, r3, 10
+ mfspr r10, SPRN_MMCR2
+ mtspr SPRN_MMCR2, r3
+ isync
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
li r3, 1
sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
mfspr r4, SPRN_MMCR0 /* save MMCR0 */
@@ -1462,6 +1498,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
std r4, VCPU_MMCR(r9)
std r5, VCPU_MMCR + 8(r9)
std r6, VCPU_MMCR + 16(r9)
+BEGIN_FTR_SECTION
+ std r10, VCPU_MMCR + 24(r9)
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
std r7, VCPU_SIAR(r9)
std r8, VCPU_SDAR(r9)
mfspr r3, SPRN_PMC1
@@ -1485,12 +1524,10 @@ BEGIN_FTR_SECTION
stw r11, VCPU_PMC + 28(r9)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
BEGIN_FTR_SECTION
- mfspr r4, SPRN_MMCR2
mfspr r5, SPRN_SIER
mfspr r6, SPRN_SPMC1
mfspr r7, SPRN_SPMC2
mfspr r8, SPRN_MMCRS
- std r4, VCPU_MMCR + 24(r9)
std r5, VCPU_SIER(r9)
stw r6, VCPU_PMC + 24(r9)
stw r7, VCPU_PMC + 28(r9)
@@ -2227,6 +2264,7 @@ machine_check_realmode:
beq mc_cont
/* If not, deliver a machine check. SRR0/1 are already set */
li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
+ ld r11, VCPU_MSR(r9)
bl kvmppc_msr_interrupt
b fast_interrupt_c_return
@@ -2431,3 +2469,21 @@ kvmppc_msr_interrupt:
li r0, 1
1: rldimi r11, r0, MSR_TS_S_LG, 63 - MSR_TS_T_LG
blr
+
+/*
+ * This works around a hardware bug on POWER8E processors, where
+ * writing a 1 to the MMCR0[PMAO] bit doesn't generate a
+ * performance monitor interrupt. Instead, when we need to have
+ * an interrupt pending, we have to arrange for a counter to overflow.
+ */
+kvmppc_fix_pmao:
+ li r3, 0
+ mtspr SPRN_MMCR2, r3
+ lis r3, (MMCR0_PMXE | MMCR0_FCECE)@h
+ ori r3, r3, MMCR0_PMCjCE | MMCR0_C56RUN
+ mtspr SPRN_MMCR0, r3
+ lis r3, 0x7fff
+ ori r3, r3, 0xffff
+ mtspr SPRN_PMC6, r3
+ isync
+ blr