Merge tag 'kvm-ppc-fixes-4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc

Fixes for PPC KVM:

- Close a hole which could possibly lead to the host timebase getting
  out of sync.

- Three fixes relating to PTEs and TLB entries for radix guests.

- Fix a bug which could lead to an interrupt never getting delivered
  to the guest, if it is pending for a guest vCPU when the vCPU gets
  offlined.

6 files changed, 159 insertions, 55 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 4c02a7378d06..e7377b73cfec 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -96,6 +96,7 @@ struct kvmppc_vcore {
 	struct kvm_vcpu *runner;
 	struct kvm *kvm;
 	u64 tb_offset;		/* guest timebase - host timebase */
+	u64 tb_offset_applied;	/* timebase offset currently in force */
 	ulong lpcr;
 	u32 arch_compat;
 	ulong pcr;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 6bee65f3cfd3..373dc1d6ef44 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -562,6 +562,7 @@ int main(void)
 	OFFSET(VCORE_NAPPING_THREADS, kvmppc_vcore, napping_threads);
 	OFFSET(VCORE_KVM, kvmppc_vcore, kvm);
 	OFFSET(VCORE_TB_OFFSET, kvmppc_vcore, tb_offset);
+	OFFSET(VCORE_TB_OFFSET_APPL, kvmppc_vcore, tb_offset_applied);
 	OFFSET(VCORE_LPCR, kvmppc_vcore, lpcr);
 	OFFSET(VCORE_PCR, kvmppc_vcore, pcr);
 	OFFSET(VCORE_DPDES, kvmppc_vcore, dpdes);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index a57eafec4dc2..361f42c8c73e 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -162,7 +162,7 @@ static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
 	if (cpu_has_feature(CPU_FTR_P9_TLBIE_BUG))
 		asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1)
 			     : : "r" (addr), "r" (kvm->arch.lpid) : "memory");
-	asm volatile("ptesync": : :"memory");
+	asm volatile("eieio ; tlbsync ; ptesync": : :"memory");
 }
 
 static void kvmppc_radix_flush_pwc(struct kvm *kvm, unsigned long addr)
@@ -173,7 +173,7 @@ static void kvmppc_radix_flush_pwc(struct kvm *kvm, unsigned long addr)
 	/* RIC=1 PRS=0 R=1 IS=2 */
 	asm volatile(PPC_TLBIE_5(%0, %1, 1, 0, 1)
 		     : : "r" (rb), "r" (kvm->arch.lpid) : "memory");
-	asm volatile("ptesync": : :"memory");
+	asm volatile("eieio ; tlbsync ; ptesync": : :"memory");
 }
 
 unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
@@ -584,7 +584,7 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
 
 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
 	if (ptep && pte_present(*ptep)) {
-		old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
+		old = kvmppc_radix_update_pte(kvm, ptep, ~0UL, 0,
 					      gpa, shift);
 		kvmppc_radix_tlbie_page(kvm, gpa, shift);
 		if ((old & _PAGE_DIRTY) && memslot->dirty_bitmap) {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 4d07fca5121c..9963f65c212b 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2441,6 +2441,7 @@ static void init_vcore_to_run(struct kvmppc_vcore *vc)
 	vc->in_guest = 0;
 	vc->napping_threads = 0;
 	vc->conferring_threads = 0;
+	vc->tb_offset_applied = 0;
 }
 
 static bool can_dynamic_split(struct kvmppc_vcore *vc, struct core_info *cip)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index bd63fa8a08b5..07ca1b2a7966 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -692,6 +692,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 22:	ld	r8,VCORE_TB_OFFSET(r5)
 	cmpdi	r8,0
 	beq	37f
+	std	r8, VCORE_TB_OFFSET_APPL(r5)
 	mftb	r6		/* current host timebase */
 	add	r8,r8,r6
 	mtspr	SPRN_TBU40,r8	/* update upper 40 bits */
@@ -940,18 +941,6 @@ FTR_SECTION_ELSE
 ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300)
 8:
 
-	/*
-	 * Set the decrementer to the guest decrementer.
-	 */
-	ld	r8,VCPU_DEC_EXPIRES(r4)
-	/* r8 is a host timebase value here, convert to guest TB */
-	ld	r5,HSTATE_KVM_VCORE(r13)
-	ld	r6,VCORE_TB_OFFSET(r5)
-	add	r8,r8,r6
-	mftb	r7
-	subf	r3,r7,r8
-	mtspr	SPRN_DEC,r3
-
 	ld	r5, VCPU_SPRG0(r4)
 	ld	r6, VCPU_SPRG1(r4)
 	ld	r7, VCPU_SPRG2(r4)
@@ -1005,6 +994,18 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300)
 	mtspr	SPRN_LPCR,r8
 	isync
 
+	/*
+	 * Set the decrementer to the guest decrementer.
+	 */
+	ld	r8,VCPU_DEC_EXPIRES(r4)
+	/* r8 is a host timebase value here, convert to guest TB */
+	ld	r5,HSTATE_KVM_VCORE(r13)
+	ld	r6,VCORE_TB_OFFSET_APPL(r5)
+	add	r8,r8,r6
+	mftb	r7
+	subf	r3,r7,r8
+	mtspr	SPRN_DEC,r3
+
 	/* Check if HDEC expires soon */
 	mfspr	r3, SPRN_HDEC
 	EXTEND_HDEC(r3)
@@ -1597,8 +1598,27 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX)
 
 guest_bypass:
 	stw	r12, STACK_SLOT_TRAP(r1)
-	mr 	r3, r12
+
+	/* Save DEC */
+	/* Do this before kvmhv_commence_exit so we know TB is guest TB */
+	ld	r3, HSTATE_KVM_VCORE(r13)
+	mfspr	r5,SPRN_DEC
+	mftb	r6
+	/* On P9, if the guest has large decr enabled, don't sign extend */
+BEGIN_FTR_SECTION
+	ld	r4, VCORE_LPCR(r3)
+	andis.	r4, r4, LPCR_LD@h
+	bne	16f
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
+	extsw	r5,r5
+16:	add	r5,r5,r6
+	/* r5 is a guest timebase value here, convert to host TB */
+	ld	r4,VCORE_TB_OFFSET_APPL(r3)
+	subf	r5,r4,r5
+	std	r5,VCPU_DEC_EXPIRES(r9)
+
 	/* Increment exit count, poke other threads to exit */
+	mr 	r3, r12
 	bl	kvmhv_commence_exit
 	nop
 	ld	r9, HSTATE_KVM_VCPU(r13)
@@ -1639,23 +1659,6 @@ guest_bypass:
 	mtspr	SPRN_PURR,r3
 	mtspr	SPRN_SPURR,r4
 
-	/* Save DEC */
-	ld	r3, HSTATE_KVM_VCORE(r13)
-	mfspr	r5,SPRN_DEC
-	mftb	r6
-	/* On P9, if the guest has large decr enabled, don't sign extend */
-BEGIN_FTR_SECTION
-	ld	r4, VCORE_LPCR(r3)
-	andis.	r4, r4, LPCR_LD@h
-	bne	16f
-END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
-	extsw	r5,r5
-16:	add	r5,r5,r6
-	/* r5 is a guest timebase value here, convert to host TB */
-	ld	r4,VCORE_TB_OFFSET(r3)
-	subf	r5,r4,r5
-	std	r5,VCPU_DEC_EXPIRES(r9)
-
 BEGIN_FTR_SECTION
 	b	8f
 END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
@@ -1905,6 +1908,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 	cmpwi	cr2, r0, 0
 	beq	cr2, 4f
 
+	/*
+	 * Radix: do eieio; tlbsync; ptesync sequence in case we
+	 * interrupted the guest between a tlbie and a ptesync.
+	 */
+	eieio
+	tlbsync
+	ptesync
+
 	/* Radix: Handle the case where the guest used an illegal PID */
 	LOAD_REG_ADDR(r4, mmu_base_pid)
 	lwz	r3, VCPU_GUEST_PID(r9)
@@ -2017,9 +2028,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 
 27:
 	/* Subtract timebase offset from timebase */
-	ld	r8,VCORE_TB_OFFSET(r5)
+	ld	r8, VCORE_TB_OFFSET_APPL(r5)
 	cmpdi	r8,0
 	beq	17f
+	li	r0, 0
+	std	r0, VCORE_TB_OFFSET_APPL(r5)
 	mftb	r6			/* current guest timebase */
 	subf	r8,r8,r6
 	mtspr	SPRN_TBU40,r8		/* update upper 40 bits */
@@ -2700,7 +2713,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 	add	r3, r3, r5
 	ld	r4, HSTATE_KVM_VCPU(r13)
 	ld	r5, HSTATE_KVM_VCORE(r13)
-	ld	r6, VCORE_TB_OFFSET(r5)
+	ld	r6, VCORE_TB_OFFSET_APPL(r5)
 	subf	r3, r6, r3	/* convert to host TB value */
 	std	r3, VCPU_DEC_EXPIRES(r4)
 
@@ -2799,7 +2812,7 @@ END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0)
 	/* Restore guest decrementer */
 	ld	r3, VCPU_DEC_EXPIRES(r4)
 	ld	r5, HSTATE_KVM_VCORE(r13)
-	ld	r6, VCORE_TB_OFFSET(r5)
+	ld	r6, VCORE_TB_OFFSET_APPL(r5)
 	add	r3, r3, r6	/* convert host TB to guest TB value */
 	mftb	r7
 	subf	r3, r7, r3
@@ -3606,12 +3619,9 @@ kvmppc_fix_pmao:
  */
 kvmhv_start_timing:
 	ld	r5, HSTATE_KVM_VCORE(r13)
-	lbz	r6, VCORE_IN_GUEST(r5)
-	cmpwi	r6, 0
-	beq	5f				/* if in guest, need to */
-	ld	r6, VCORE_TB_OFFSET(r5)		/* subtract timebase offset */
-5:	mftb	r5
-	subf	r5, r6, r5
+	ld	r6, VCORE_TB_OFFSET_APPL(r5)
+	mftb	r5
+	subf	r5, r6, r5	/* subtract current timebase offset */
 	std	r3, VCPU_CUR_ACTIVITY(r4)
 	std	r5, VCPU_ACTIVITY_START(r4)
 	blr
@@ -3622,15 +3632,12 @@ kvmhv_start_timing:
  */
 kvmhv_accumulate_time:
 	ld	r5, HSTATE_KVM_VCORE(r13)
-	lbz	r8, VCORE_IN_GUEST(r5)
-	cmpwi	r8, 0
-	beq	4f				/* if in guest, need to */
-	ld	r8, VCORE_TB_OFFSET(r5)		/* subtract timebase offset */
-4:	ld	r5, VCPU_CUR_ACTIVITY(r4)
+	ld	r8, VCORE_TB_OFFSET_APPL(r5)
+	ld	r5, VCPU_CUR_ACTIVITY(r4)
 	ld	r6, VCPU_ACTIVITY_START(r4)
 	std	r3, VCPU_CUR_ACTIVITY(r4)
 	mftb	r7
-	subf	r7, r8, r7
+	subf	r7, r8, r7	/* subtract current timebase offset */
 	std	r7, VCPU_ACTIVITY_START(r4)
 	cmpdi	r5, 0
 	beqlr
diff --git a/arch/powerpc/kvm/book3s_xive_template.c b/arch/powerpc/kvm/book3s_xive_template.c
index c7a5deadd1cc..99c3620b40d9 100644
--- a/arch/powerpc/kvm/book3s_xive_template.c
+++ b/arch/powerpc/kvm/book3s_xive_template.c
@@ -11,6 +11,9 @@
 #define XGLUE(a,b) a##b
 #define GLUE(a,b) XGLUE(a,b)
 
+/* Dummy interrupt used when taking interrupts out of a queue in H_CPPR */
+#define XICS_DUMMY	1
+
 static void GLUE(X_PFX,ack_pending)(struct kvmppc_xive_vcpu *xc)
 {
 	u8 cppr;
@@ -205,6 +208,10 @@ skip_ipi:
 				goto skip_ipi;
 		}
 
+		/* If it's the dummy interrupt, continue searching */
+		if (hirq == XICS_DUMMY)
+			goto skip_ipi;
+
 		/* If fetching, update queue pointers */
 		if (scan_type == scan_fetch) {
 			q->idx = idx;
@@ -385,9 +392,76 @@ static void GLUE(X_PFX,push_pending_to_hw)(struct kvmppc_xive_vcpu *xc)
 	__x_writeb(prio, __x_tima + TM_SPC_SET_OS_PENDING);
 }
 
+static void GLUE(X_PFX,scan_for_rerouted_irqs)(struct kvmppc_xive *xive,
+					       struct kvmppc_xive_vcpu *xc)
+{
+	unsigned int prio;
+
+	/* For each priority that is now masked */
+	for (prio = xc->cppr; prio < KVMPPC_XIVE_Q_COUNT; prio++) {
+		struct xive_q *q = &xc->queues[prio];
+		struct kvmppc_xive_irq_state *state;
+		struct kvmppc_xive_src_block *sb;
+		u32 idx, toggle, entry, irq, hw_num;
+		struct xive_irq_data *xd;
+		__be32 *qpage;
+		u16 src;
+
+		idx = q->idx;
+		toggle = q->toggle;
+		qpage = READ_ONCE(q->qpage);
+		if (!qpage)
+			continue;
+
+		/* For each interrupt in the queue */
+		for (;;) {
+			entry = be32_to_cpup(qpage + idx);
+
+			/* No more ? */
+			if ((entry >> 31) == toggle)
+				break;
+			irq = entry & 0x7fffffff;
+
+			/* Skip dummies and IPIs */
+			if (irq == XICS_DUMMY || irq == XICS_IPI)
+				goto next;
+			sb = kvmppc_xive_find_source(xive, irq, &src);
+			if (!sb)
+				goto next;
+			state = &sb->irq_state[src];
+
+			/* Has it been rerouted ? */
+			if (xc->server_num == state->act_server)
+				goto next;
+
+			/*
+			 * Allright, it *has* been re-routed, kill it from
+			 * the queue.
+			 */
+			qpage[idx] = cpu_to_be32((entry & 0x80000000) | XICS_DUMMY);
+
+			/* Find the HW interrupt */
+			kvmppc_xive_select_irq(state, &hw_num, &xd);
+
+			/* If it's not an LSI, set PQ to 11 the EOI will force a resend */
+			if (!(xd->flags & XIVE_IRQ_FLAG_LSI))
+				GLUE(X_PFX,esb_load)(xd, XIVE_ESB_SET_PQ_11);
+
+			/* EOI the source */
+			GLUE(X_PFX,source_eoi)(hw_num, xd);
+
+		next:
+			idx = (idx + 1) & q->msk;
+			if (idx == 0)
+				toggle ^= 1;
+		}
+	}
+}
+
 X_STATIC int GLUE(X_PFX,h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr)
 {
 	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
+	struct kvmppc_xive *xive = vcpu->kvm->arch.xive;
 	u8 old_cppr;
 
 	pr_devel("H_CPPR(cppr=%ld)\n", cppr);
@@ -407,14 +481,34 @@ X_STATIC int GLUE(X_PFX,h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr)
 	 */
 	smp_mb();
 
-	/*
-	 * We are masking less, we need to look for pending things
-	 * to deliver and set VP pending bits accordingly to trigger
-	 * a new interrupt otherwise we might miss MFRR changes for
-	 * which we have optimized out sending an IPI signal.
-	 */
-	if (cppr > old_cppr)
+	if (cppr > old_cppr) {
+		/*
+		 * We are masking less, we need to look for pending things
+		 * to deliver and set VP pending bits accordingly to trigger
+		 * a new interrupt otherwise we might miss MFRR changes for
+		 * which we have optimized out sending an IPI signal.
+		 */
 		GLUE(X_PFX,push_pending_to_hw)(xc);
+	} else {
+		/*
+		 * We are masking more, we need to check the queue for any
+		 * interrupt that has been routed to another CPU, take
+		 * it out (replace it with the dummy) and retrigger it.
+		 *
+		 * This is necessary since those interrupts may otherwise
+		 * never be processed, at least not until this CPU restores
+		 * its CPPR.
+		 *
+		 * This is in theory racy vs. HW adding new interrupts to
+		 * the queue. In practice this works because the interesting
+		 * cases are when the guest has done a set_xive() to move the
+		 * interrupt away, which flushes the xive, followed by the
+		 * target CPU doing a H_CPPR. So any new interrupt coming into
+		 * the queue must still be routed to us and isn't a source
+		 * of concern.
+		 */
+		GLUE(X_PFX,scan_for_rerouted_irqs)(xive, xc);
+	}
 
 	/* Apply new CPPR */
 	xc->hw_cppr = cppr;