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KVM: arm64: Remove VPIPT I-cache handling

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We have some special handling for VPIPT I-cache in critical parts
of the cache and TLB maintenance. Remove it.

Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20231204143606.1806432-2-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Marc Zyngier 2023-12-04 14:36:04 +00:00 committed by Will Deacon
parent 2cc14f52ae
commit ced242ba9d
4 changed files with 1 additions and 82 deletions
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7
arch/arm64/include/asm/kvm_mmu.h
View File

@ -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

2
arch/arm64/kvm/hyp/nvhe/pkvm.c
View File

@ -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(). */

61
arch/arm64/kvm/hyp/nvhe/tlb.c
View File

@ -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);
}

13
arch/arm64/kvm/hyp/vhe/tlb.c
View File

@ -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);
}