| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2015 - ARM Ltd |
| * Author: Marc Zyngier <marc.zyngier@arm.com> |
| */ |
| |
| #include <asm/kvm_hyp.h> |
| #include <asm/kvm_mmu.h> |
| #include <asm/tlbflush.h> |
| |
| struct tlb_inv_context { |
| u64 tcr; |
| }; |
| |
| static void __tlb_switch_to_guest(struct kvm_s2_mmu *mmu, |
| struct tlb_inv_context *cxt) |
| { |
| if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) { |
| u64 val; |
| |
| /* |
| * For CPUs that are affected by ARM 1319367, we need to |
| * avoid a host Stage-1 walk while we have the guest's |
| * VMID set in the VTTBR in order to invalidate TLBs. |
| * We're guaranteed that the S1 MMU is enabled, so we can |
| * simply set the EPD bits to avoid any further TLB fill. |
| */ |
| val = cxt->tcr = read_sysreg_el1(SYS_TCR); |
| val |= TCR_EPD1_MASK | TCR_EPD0_MASK; |
| write_sysreg_el1(val, SYS_TCR); |
| isb(); |
| } |
| |
| /* |
| * __load_guest_stage2() includes an ISB only when the AT |
| * workaround is applied. Take care of the opposite condition, |
| * ensuring that we always have an ISB, but not two ISBs back |
| * to back. |
| */ |
| __load_guest_stage2(mmu); |
| asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT)); |
| } |
| |
| static void __tlb_switch_to_host(struct tlb_inv_context *cxt) |
| { |
| write_sysreg(0, vttbr_el2); |
| |
| if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) { |
| /* Ensure write of the host VMID */ |
| isb(); |
| /* Restore the host's TCR_EL1 */ |
| write_sysreg_el1(cxt->tcr, SYS_TCR); |
| } |
| } |
| |
| void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, |
| phys_addr_t ipa, int level) |
| { |
| struct tlb_inv_context cxt; |
| |
| dsb(ishst); |
| |
| /* Switch to requested VMID */ |
| mmu = kern_hyp_va(mmu); |
| __tlb_switch_to_guest(mmu, &cxt); |
| |
| /* |
| * We could do so much better if we had the VA as well. |
| * Instead, we invalidate Stage-2 for this IPA, and the |
| * whole of Stage-1. Weep... |
| */ |
| ipa >>= 12; |
| __tlbi_level(ipas2e1is, ipa, level); |
| |
| /* |
| * We have to ensure completion of the invalidation at Stage-2, |
| * since a table walk on another CPU could refill a TLB with a |
| * complete (S1 + S2) walk based on the old Stage-2 mapping if |
| * the Stage-1 invalidation happened first. |
| */ |
| dsb(ish); |
| __tlbi(vmalle1is); |
| 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()) |
| __flush_icache_all(); |
| |
| __tlb_switch_to_host(&cxt); |
| } |
| |
| void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu) |
| { |
| struct tlb_inv_context cxt; |
| |
| dsb(ishst); |
| |
| /* Switch to requested VMID */ |
| mmu = kern_hyp_va(mmu); |
| __tlb_switch_to_guest(mmu, &cxt); |
| |
| __tlbi(vmalls12e1is); |
| dsb(ish); |
| isb(); |
| |
| __tlb_switch_to_host(&cxt); |
| } |
| |
| void __kvm_tlb_flush_local_vmid(struct kvm_s2_mmu *mmu) |
| { |
| struct tlb_inv_context cxt; |
| |
| /* Switch to requested VMID */ |
| mmu = kern_hyp_va(mmu); |
| __tlb_switch_to_guest(mmu, &cxt); |
| |
| __tlbi(vmalle1); |
| dsb(nsh); |
| isb(); |
| |
| __tlb_switch_to_host(&cxt); |
| } |
| |
| 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); |
| } |