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[35.195.168.105]) by smtp.gmail.com with ESMTPSA id p20sm2282579wmq.10.2021.06.02.03.58.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Jun 2021 03:58:30 -0700 (PDT) Date: Wed, 2 Jun 2021 10:58:28 +0000 From: Quentin Perret To: Yanan Wang Subject: Re: [PATCH v5 5/6] KVM: arm64: Move I-cache flush to the fault handlers Message-ID: References: <20210415115032.35760-1-wangyanan55@huawei.com> <20210415115032.35760-6-wangyanan55@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210415115032.35760-6-wangyanan55@huawei.com> Cc: kvm@vger.kernel.org, Marc Zyngier , linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Thursday 15 Apr 2021 at 19:50:31 (+0800), Yanan Wang wrote: > In this patch, we move invalidation of I-cache to the fault handlers to Nit: please avoid using 'This patch' in commit messages, see Documentation/process/submitting-patches.rst. > avoid unnecessary I-cache maintenances. On the map path, invalidate the > I-cache if we are going to create an executable stage-2 mapping for guest. > And on the permission path, invalidate the I-cache if we are going to add > an executable permission to the existing guest stage-2 mapping. > > Signed-off-by: Yanan Wang > --- > arch/arm64/include/asm/kvm_mmu.h | 15 -------------- > arch/arm64/kvm/hyp/pgtable.c | 35 +++++++++++++++++++++++++++++++- > arch/arm64/kvm/mmu.c | 9 +------- > 3 files changed, 35 insertions(+), 24 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h > index e9b163c5f023..155492fe5b15 100644 > --- a/arch/arm64/include/asm/kvm_mmu.h > +++ b/arch/arm64/include/asm/kvm_mmu.h > @@ -187,21 +187,6 @@ static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu) > return (vcpu_read_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; > } > > -static inline void __invalidate_icache_guest_page(kvm_pfn_t pfn, > - unsigned long size) > -{ > - if (icache_is_aliasing()) { > - /* any kind of VIPT cache */ > - __flush_icache_all(); > - } else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) { > - /* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */ > - void *va = page_address(pfn_to_page(pfn)); > - > - invalidate_icache_range((unsigned long)va, > - (unsigned long)va + size); > - } > -} > - > void kvm_set_way_flush(struct kvm_vcpu *vcpu); > void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled); > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index b480f6d1171e..9f4429d80df0 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -568,6 +568,26 @@ static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte) > return memattr == KVM_S2_MEMATTR(pgt, NORMAL); > } > > +static bool stage2_pte_executable(kvm_pte_t pte) > +{ > + return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN); > +} > + > +static void stage2_invalidate_icache(void *addr, u64 size) > +{ > + if (icache_is_aliasing()) { > + /* Any kind of VIPT cache */ > + __flush_icache_all(); > + } else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) { > + /* > + * See comment in __kvm_tlb_flush_vmid_ipa(). > + * Invalidate PIPT, or VPIPT at EL2. > + */ > + invalidate_icache_range((unsigned long)addr, > + (unsigned long)addr + size); > + } > +} > + > static void stage2_put_pte(kvm_pte_t *ptep, struct kvm_s2_mmu *mmu, u64 addr, > u32 level, struct kvm_pgtable_mm_ops *mm_ops) > { > @@ -618,6 +638,10 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level, > if (stage2_pte_cacheable(pgt, new) && !stage2_has_fwb(pgt)) > __flush_dcache_area(mm_ops->phys_to_virt(phys), > granule); > + > + if (stage2_pte_executable(new)) > + stage2_invalidate_icache(mm_ops->phys_to_virt(phys), > + granule); > } > > smp_store_release(ptep, new); > @@ -896,8 +920,17 @@ static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > * but worst-case the access flag update gets lost and will be > * set on the next access instead. > */ > - if (data->pte != pte) > + if (data->pte != pte) { > + /* > + * Invalidate the instruction cache before updating > + * if we are going to add the executable permission > + * for the guest stage-2 PTE. > + */ > + if (!stage2_pte_executable(*ptep) && stage2_pte_executable(pte)) > + stage2_invalidate_icache(kvm_pte_follow(pte, data->mm_ops), > + kvm_granule_size(level)); > WRITE_ONCE(*ptep, pte); > + } As for the dcache stuff, it seems like this would be best placed in an optional mm_ops callback, and have the kernel implement it. Thanks, Quentin _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm