From: cdall@linaro.org (Christoffer Dall)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 06/10] KVM: arm/arm64: Only clean the dcache on translation fault
Date: Mon, 16 Oct 2017 22:08:11 +0200 [thread overview]
Message-ID: <20171016200811.GH1845@lvm> (raw)
In-Reply-To: <20171009152032.27804-7-marc.zyngier@arm.com>
On Mon, Oct 09, 2017 at 04:20:28PM +0100, Marc Zyngier wrote:
> The only case where we actually need to perform a dache maintenance
> is when we map the page for the first time, and subsequent permission
> faults do not require cache maintenance. Let's make it conditional
> on not being a permission fault (and thus a translation fault).
Why do we actually need to do any dcache maintenance when faulting in a
page?
Is this for the case when the stage 1 MMU is disabled, or to support
guest mappings using uncached attributes? Can we do better, for example
by only flushing the cache if the guest MMU is disabled?
Beyond that:
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> virt/kvm/arm/mmu.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 1d47da22f75c..1911fadde88b 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -1400,7 +1400,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> new_pmd = kvm_s2pmd_mkwrite(new_pmd);
> kvm_set_pfn_dirty(pfn);
> }
> - coherent_dcache_guest_page(vcpu, pfn, PMD_SIZE);
> +
> + if (fault_status != FSC_PERM)
> + coherent_dcache_guest_page(vcpu, pfn, PMD_SIZE);
>
> if (exec_fault) {
> new_pmd = kvm_s2pmd_mkexec(new_pmd);
> @@ -1416,7 +1418,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> kvm_set_pfn_dirty(pfn);
> mark_page_dirty(kvm, gfn);
> }
> - coherent_dcache_guest_page(vcpu, pfn, PAGE_SIZE);
> +
> + if (fault_status != FSC_PERM)
> + coherent_dcache_guest_page(vcpu, pfn, PAGE_SIZE);
>
> if (exec_fault) {
> new_pte = kvm_s2pte_mkexec(new_pte);
> --
> 2.14.1
>
next prev parent reply other threads:[~2017-10-16 20:08 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 15:20 [PATCH 00/10] arm/arm64: KVM: limit icache invalidation to prefetch aborts Marc Zyngier
2017-10-09 15:20 ` [PATCH 01/10] KVM: arm/arm64: Split dcache/icache flushing Marc Zyngier
2017-10-16 20:07 ` Christoffer Dall
2017-10-17 8:57 ` Marc Zyngier
2017-10-17 14:28 ` Christoffer Dall
2017-10-17 14:41 ` Marc Zyngier
2017-10-16 21:35 ` Roy Franz (Cavium)
2017-10-17 6:44 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 02/10] arm64: KVM: Add invalidate_icache_range helper Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-19 16:47 ` Will Deacon
2017-10-20 13:41 ` Marc Zyngier
2017-10-09 15:20 ` [PATCH 03/10] arm: KVM: Add optimized PIPT icache flushing Marc Zyngier
2017-10-16 20:07 ` Christoffer Dall
2017-10-17 9:26 ` Marc Zyngier
2017-10-17 14:34 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 04/10] arm64: KVM: PTE/PMD S2 XN bit definition Marc Zyngier
2017-10-16 20:07 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 05/10] KVM: arm/arm64: Limit icache invalidation to prefetch aborts Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 06/10] KVM: arm/arm64: Only clean the dcache on translation fault Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall [this message]
2017-10-17 9:34 ` Marc Zyngier
2017-10-17 14:36 ` Christoffer Dall
2017-10-17 14:52 ` Marc Zyngier
2017-10-09 15:20 ` [PATCH 07/10] KVM: arm/arm64: Preserve Exec permission across R/W permission faults Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-17 11:22 ` Marc Zyngier
2017-10-17 14:46 ` Christoffer Dall
2017-10-17 15:04 ` Marc Zyngier
2017-10-09 15:20 ` [PATCH 08/10] KVM: arm/arm64: Drop vcpu parameter from coherent_{d, i}cache_guest_page Marc Zyngier
2017-10-16 20:08 ` [PATCH 08/10] KVM: arm/arm64: Drop vcpu parameter from coherent_{d,i}cache_guest_page Christoffer Dall
2017-10-09 15:20 ` [PATCH 09/10] KVM: arm/arm64: Detangle kvm_mmu.h from kvm_hyp.h Marc Zyngier
2017-10-16 20:08 ` Christoffer Dall
2017-10-09 15:20 ` [PATCH 10/10] arm: KVM: Use common implementation for all flushes to PoC Marc Zyngier
2017-10-16 20:06 ` Christoffer Dall
2017-10-17 12:40 ` Marc Zyngier
2017-10-17 14:48 ` Christoffer Dall
2017-10-16 20:59 ` [PATCH 00/10] arm/arm64: KVM: limit icache invalidation to prefetch aborts Christoffer Dall
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