Merge branch 'for-next/rip-vpipt' into for-next/core

willdeacon · willdeacon · commit 30431774fe6e · 2024-01-04T12:28:14.000Z
* for-next/rip-vpipt:
  arm64: Rename reserved values for CTR_EL0.L1Ip
  arm64: Kill detection of VPIPT i-cache policy
  KVM: arm64: Remove VPIPT I-cache handling
diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
@@ -58,7 +58,6 @@ static inline unsigned int arch_slab_minalign(void)
 #define CTR_L1IP(ctr)		SYS_FIELD_GET(CTR_EL0, L1Ip, ctr)
 
 #define ICACHEF_ALIASING	0
-#define ICACHEF_VPIPT		1
 extern unsigned long __icache_flags;
 
 /*
@@ -70,11 +69,6 @@ static inline int icache_is_aliasing(void)
 	return test_bit(ICACHEF_ALIASING, &__icache_flags);
 }
 
-static __always_inline int icache_is_vpipt(void)
-{
-	return test_bit(ICACHEF_VPIPT, &__icache_flags);
-}
-
 static inline u32 cache_type_cwg(void)
 {
 	return SYS_FIELD_GET(CTR_EL0, CWG, read_cpuid_cachetype());
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
@@ -243,13 +243,6 @@ static inline size_t __invalidate_icache_max_range(void)
 
 static inline void __invalidate_icache_guest_page(void *va, size_t size)
 {
-	/*
-	 * VPIPT I-cache maintenance must be done from EL2. See comment in the
-	 * nVHE flavor of __kvm_tlb_flush_vmid_ipa().
-	 */
-	if (icache_is_vpipt() && read_sysreg(CurrentEL) != CurrentEL_EL2)
-		return;
-
 	/*
 	 * Blow the whole I-cache if it is aliasing (i.e. VIPT) or the
 	 * invalidation range exceeds our arbitrary limit on invadations by
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
@@ -36,8 +36,6 @@ static struct cpuinfo_arm64 boot_cpu_data;
 static inline const char *icache_policy_str(int l1ip)
 {
 	switch (l1ip) {
-	case CTR_EL0_L1Ip_VPIPT:
-		return "VPIPT";
 	case CTR_EL0_L1Ip_VIPT:
 		return "VIPT";
 	case CTR_EL0_L1Ip_PIPT:
@@ -388,9 +386,6 @@ static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
 	switch (l1ip) {
 	case CTR_EL0_L1Ip_PIPT:
 		break;
-	case CTR_EL0_L1Ip_VPIPT:
-		set_bit(ICACHEF_VPIPT, &__icache_flags);
-		break;
 	case CTR_EL0_L1Ip_VIPT:
 	default:
 		/* Assume aliasing */
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -12,7 +12,7 @@
 #include <nvhe/pkvm.h>
 #include <nvhe/trap_handler.h>
 
-/* Used by icache_is_vpipt(). */
+/* Used by icache_is_aliasing(). */
 unsigned long __icache_flags;
 
 /* Used by kvm_get_vttbr(). */
diff --git a/arch/arm64/kvm/hyp/nvhe/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c
@@ -105,28 +105,6 @@ void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu,
 	dsb(ish);
 	isb();
 
-	/*
-	 * If the host is running at EL1 and we have a VPIPT I-cache,
-	 * then we must perform I-cache maintenance at EL2 in order for
-	 * it to have an effect on the guest. Since the guest cannot hit
-	 * I-cache lines allocated with a different VMID, we don't need
-	 * to worry about junk out of guest reset (we nuke the I-cache on
-	 * VMID rollover), but we do need to be careful when remapping
-	 * executable pages for the same guest. This can happen when KSM
-	 * takes a CoW fault on an executable page, copies the page into
-	 * a page that was previously mapped in the guest and then needs
-	 * to invalidate the guest view of the I-cache for that page
-	 * from EL1. To solve this, we invalidate the entire I-cache when
-	 * unmapping a page from a guest if we have a VPIPT I-cache but
-	 * the host is running at EL1. As above, we could do better if
-	 * we had the VA.
-	 *
-	 * The moral of this story is: if you have a VPIPT I-cache, then
-	 * you should be running with VHE enabled.
-	 */
-	if (icache_is_vpipt())
-		icache_inval_all_pou();
-
 	__tlb_switch_to_host(&cxt);
 }
 
@@ -157,28 +135,6 @@ void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
 	dsb(nsh);
 	isb();
 
-	/*
-	 * If the host is running at EL1 and we have a VPIPT I-cache,
-	 * then we must perform I-cache maintenance at EL2 in order for
-	 * it to have an effect on the guest. Since the guest cannot hit
-	 * I-cache lines allocated with a different VMID, we don't need
-	 * to worry about junk out of guest reset (we nuke the I-cache on
-	 * VMID rollover), but we do need to be careful when remapping
-	 * executable pages for the same guest. This can happen when KSM
-	 * takes a CoW fault on an executable page, copies the page into
-	 * a page that was previously mapped in the guest and then needs
-	 * to invalidate the guest view of the I-cache for that page
-	 * from EL1. To solve this, we invalidate the entire I-cache when
-	 * unmapping a page from a guest if we have a VPIPT I-cache but
-	 * the host is running at EL1. As above, we could do better if
-	 * we had the VA.
-	 *
-	 * The moral of this story is: if you have a VPIPT I-cache, then
-	 * you should be running with VHE enabled.
-	 */
-	if (icache_is_vpipt())
-		icache_inval_all_pou();
-
 	__tlb_switch_to_host(&cxt);
 }
 
@@ -205,10 +161,6 @@ void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
 	dsb(ish);
 	isb();
 
-	/* See the comment in __kvm_tlb_flush_vmid_ipa() */
-	if (icache_is_vpipt())
-		icache_inval_all_pou();
-
 	__tlb_switch_to_host(&cxt);
 }
 
@@ -246,18 +198,5 @@ void __kvm_flush_vm_context(void)
 	/* Same remark as in __tlb_switch_to_guest() */
 	dsb(ish);
 	__tlbi(alle1is);
-
-	/*
-	 * VIPT and PIPT caches are not affected by VMID, so no maintenance
-	 * is necessary across a VMID rollover.
-	 *
-	 * VPIPT caches constrain lookup and maintenance to the active VMID,
-	 * so we need to invalidate lines with a stale VMID to avoid an ABA
-	 * race after multiple rollovers.
-	 *
-	 */
-	if (icache_is_vpipt())
-		asm volatile("ic ialluis");
-
 	dsb(ish);
 }
diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c
@@ -216,18 +216,5 @@ void __kvm_flush_vm_context(void)
 {
 	dsb(ishst);
 	__tlbi(alle1is);
-
-	/*
-	 * VIPT and PIPT caches are not affected by VMID, so no maintenance
-	 * is necessary across a VMID rollover.
-	 *
-	 * VPIPT caches constrain lookup and maintenance to the active VMID,
-	 * so we need to invalidate lines with a stale VMID to avoid an ABA
-	 * race after multiple rollovers.
-	 *
-	 */
-	if (icache_is_vpipt())
-		asm volatile("ic ialluis");
-
 	dsb(ish);
 }
diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
@@ -2004,9 +2004,10 @@ Field	27:24	CWG
 Field	23:20	ERG
 Field	19:16	DminLine
 Enum	15:14	L1Ip
-	0b00	VPIPT
+	# This was named as VPIPT in the ARM but now documented as reserved
+	0b00	RESERVED_VPIPT
 	# This is named as AIVIVT in the ARM but documented as reserved
-	0b01	RESERVED
+	0b01	RESERVED_AIVIVT
 	0b10	VIPT
 	0b11	PIPT
 EndEnum
