From ced242ba9d7cb3571f6e0f165f643cb832d52148 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 4 Dec 2023 14:36:04 +0000 Subject: KVM: arm64: Remove VPIPT I-cache handling We have some special handling for VPIPT I-cache in critical parts of the cache and TLB maintenance. Remove it. Reviewed-by: Zenghui Yu Reviewed-by: Anshuman Khandual Signed-off-by: Marc Zyngier Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20231204143606.1806432-2-maz@kernel.org Signed-off-by: Will Deacon --- arch/arm64/include/asm/kvm_mmu.h | 7 ----- arch/arm64/kvm/hyp/nvhe/pkvm.c | 2 +- arch/arm64/kvm/hyp/nvhe/tlb.c | 61 ---------------------------------------- arch/arm64/kvm/hyp/vhe/tlb.c | 13 --------- 4 files changed, 1 insertion(+), 82 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 49e0d4b36bd0..e3e793d0ec30 100644 --- 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/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 9d23a51d7f75..b29f15418c0a 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -12,7 +12,7 @@ #include #include -/* 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 index 1b265713d6be..a60fb13e2192 100644 --- 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 index b636b4111dbf..b32e2940df7d 100644 --- 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); } -- cgit