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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <linux/irqflags.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/tlbflush.h>
struct tlb_inv_context {
unsigned long flags;
u64 tcr;
u64 sctlr;
};
static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
u64 val;
local_irq_save(cxt->flags);
if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT_VHE)) {
/*
* For CPUs that are affected by ARM errata 1165522 or 1530923,
* we cannot trust stage-1 to be in a correct state at that
* point. Since we do not want to force a full load of the
* vcpu state, we prevent the EL1 page-table walker to
* allocate new TLBs. This is done by setting the EPD bits
* in the TCR_EL1 register. We also need to prevent it to
* allocate IPA->PA walks, so we enable the S1 MMU...
*/
val = cxt->tcr = read_sysreg_el1(SYS_TCR);
val |= TCR_EPD1_MASK | TCR_EPD0_MASK;
write_sysreg_el1(val, SYS_TCR);
val = cxt->sctlr = read_sysreg_el1(SYS_SCTLR);
val |= SCTLR_ELx_M;
write_sysreg_el1(val, SYS_SCTLR);
}
/*
* With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
* most TLB operations target EL2/EL0. In order to affect the
* guest TLBs (EL1/EL0), we need to change one of these two
* bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
* let's flip TGE before executing the TLB operation.
*
* ARM erratum 1165522 requires some special handling (again),
* as we need to make sure both stages of translation are in
* place before clearing TGE. __load_guest_stage2() already
* has an ISB in order to deal with this.
*/
__load_guest_stage2(kvm);
val = read_sysreg(hcr_el2);
val &= ~HCR_TGE;
write_sysreg(val, hcr_el2);
isb();
}
static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT_NVHE)) {
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(kvm);
isb();
}
static void __hyp_text __tlb_switch_to_guest(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
if (has_vhe())
__tlb_switch_to_guest_vhe(kvm, cxt);
else
__tlb_switch_to_guest_nvhe(kvm, cxt);
}
static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
/*
* We're done with the TLB operation, let's restore the host's
* view of HCR_EL2.
*/
write_sysreg(0, vttbr_el2);
write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
isb();
if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT_VHE)) {
/* Restore the registers to what they were */
write_sysreg_el1(cxt->tcr, SYS_TCR);
write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
}
local_irq_restore(cxt->flags);
}
static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
write_sysreg(0, vttbr_el2);
if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT_NVHE)) {
/* Ensure write of the host VMID */
isb();
/* Restore the host's TCR_EL1 */
write_sysreg_el1(cxt->tcr, SYS_TCR);
}
}
static void __hyp_text __tlb_switch_to_host(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
if (has_vhe())
__tlb_switch_to_host_vhe(kvm, cxt);
else
__tlb_switch_to_host_nvhe(kvm, cxt);
}
void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
{
struct tlb_inv_context cxt;
dsb(ishst);
/* Switch to requested VMID */
kvm = kern_hyp_va(kvm);
__tlb_switch_to_guest(kvm, &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(ipas2e1is, ipa);
/*
* 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 (!has_vhe() && icache_is_vpipt())
__flush_icache_all();
__tlb_switch_to_host(kvm, &cxt);
}
void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm)
{
struct tlb_inv_context cxt;
dsb(ishst);
/* Switch to requested VMID */
kvm = kern_hyp_va(kvm);
__tlb_switch_to_guest(kvm, &cxt);
__tlbi(vmalls12e1is);
dsb(ish);
isb();
__tlb_switch_to_host(kvm, &cxt);
}
void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm);
struct tlb_inv_context cxt;
/* Switch to requested VMID */
__tlb_switch_to_guest(kvm, &cxt);
__tlbi(vmalle1);
dsb(nsh);
isb();
__tlb_switch_to_host(kvm, &cxt);
}
void __hyp_text __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);
}
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