From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751756AbeEDQWv (ORCPT ); Fri, 4 May 2018 12:22:51 -0400 Received: from foss.arm.com ([217.140.101.70]:56224 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454AbeEDQWu (ORCPT ); Fri, 4 May 2018 12:22:50 -0400 From: Punit Agrawal To: Christoffer Dall Cc: marc.zyngier@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/4] KVM: arm/arm64: Share common code in user_mem_abort() References: <20180501102659.13188-1-punit.agrawal@arm.com> <20180501102659.13188-2-punit.agrawal@arm.com> <20180504113813.GD10191@C02W217FHV2R.local> Date: Fri, 04 May 2018 17:22:48 +0100 In-Reply-To: <20180504113813.GD10191@C02W217FHV2R.local> (Christoffer Dall's message of "Fri, 4 May 2018 13:38:13 +0200") Message-ID: <874ljnl7af.fsf@e105922-lin.cambridge.arm.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christoffer Dall writes: > On Tue, May 01, 2018 at 11:26:56AM +0100, Punit Agrawal wrote: >> The code for operations such as marking the pfn as dirty, and >> dcache/icache maintenance during stage 2 fault handling is duplicated >> between normal pages and PMD hugepages. >> >> Instead of creating another copy of the operations when we introduce >> PUD hugepages, let's share them across the different pagesizes. >> >> Signed-off-by: Punit Agrawal >> Reviewed-by: Christoffer Dall >> Cc: Marc Zyngier >> --- >> virt/kvm/arm/mmu.c | 66 +++++++++++++++++++++++++++------------------- >> 1 file changed, 39 insertions(+), 27 deletions(-) >> >> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c >> index 7f6a944db23d..686fc6a4b866 100644 >> --- a/virt/kvm/arm/mmu.c >> +++ b/virt/kvm/arm/mmu.c [...] >> @@ -1517,28 +1533,34 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> if (mmu_notifier_retry(kvm, mmu_seq)) >> goto out_unlock; >> >> - if (!hugetlb && !force_pte) >> + if (!hugetlb && !force_pte) { >> hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); >> + /* >> + * Only PMD_SIZE transparent hugepages(THP) are >> + * currently supported. This code will need to be >> + * updated to support other THP sizes. >> + */ >> + if (hugetlb) >> + vma_pagesize = PMD_SIZE; > > nit: this is a bit of a trap waiting to happen, as the suggested > semantics of hugetlb is now hugetlbfs and not THP. > > It may be slightly nicer to do do: > > if (transparent_hugepage_adjust(&pfn, &fault_ipa)) > vma_pagesize = PMD_SIZE; I should've noticed this. I'll incorporate your suggestion and update the condition below using hugetlb to rely on vma_pagesize instead. Thanks, Punit > >> + } >> + >> + if (writable) >> + kvm_set_pfn_dirty(pfn); >> + >> + if (fault_status != FSC_PERM) >> + clean_dcache_guest_page(pfn, vma_pagesize); >> + >> + if (exec_fault) >> + invalidate_icache_guest_page(pfn, vma_pagesize); >> >> if (hugetlb) { >> pmd_t new_pmd = pfn_pmd(pfn, mem_type); >> new_pmd = pmd_mkhuge(new_pmd); >> - if (writable) { >> + if (writable) >> new_pmd = kvm_s2pmd_mkwrite(new_pmd); >> - kvm_set_pfn_dirty(pfn); >> - } >> >> - if (fault_status != FSC_PERM) >> - clean_dcache_guest_page(pfn, PMD_SIZE); >> - >> - if (exec_fault) { >> + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) >> new_pmd = kvm_s2pmd_mkexec(new_pmd); >> - invalidate_icache_guest_page(pfn, PMD_SIZE); >> - } else if (fault_status == FSC_PERM) { >> - /* Preserve execute if XN was already cleared */ >> - if (stage2_is_exec(kvm, fault_ipa)) >> - new_pmd = kvm_s2pmd_mkexec(new_pmd); >> - } >> >> ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); >> } else { >> @@ -1546,21 +1568,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> >> if (writable) { >> new_pte = kvm_s2pte_mkwrite(new_pte); >> - kvm_set_pfn_dirty(pfn); >> mark_page_dirty(kvm, gfn); >> } >> >> - if (fault_status != FSC_PERM) >> - clean_dcache_guest_page(pfn, PAGE_SIZE); >> - >> - if (exec_fault) { >> + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) >> new_pte = kvm_s2pte_mkexec(new_pte); >> - invalidate_icache_guest_page(pfn, PAGE_SIZE); >> - } else if (fault_status == FSC_PERM) { >> - /* Preserve execute if XN was already cleared */ >> - if (stage2_is_exec(kvm, fault_ipa)) >> - new_pte = kvm_s2pte_mkexec(new_pte); >> - } >> >> ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags); >> } >> -- >> 2.17.0 >> > > Otherwise looks good. > > Thanks, > -Christoffer > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 From: punit.agrawal@arm.com (Punit Agrawal) Date: Fri, 04 May 2018 17:22:48 +0100 Subject: [PATCH v2 1/4] KVM: arm/arm64: Share common code in user_mem_abort() In-Reply-To: <20180504113813.GD10191@C02W217FHV2R.local> (Christoffer Dall's message of "Fri, 4 May 2018 13:38:13 +0200") References: <20180501102659.13188-1-punit.agrawal@arm.com> <20180501102659.13188-2-punit.agrawal@arm.com> <20180504113813.GD10191@C02W217FHV2R.local> Message-ID: <874ljnl7af.fsf@e105922-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Christoffer Dall writes: > On Tue, May 01, 2018 at 11:26:56AM +0100, Punit Agrawal wrote: >> The code for operations such as marking the pfn as dirty, and >> dcache/icache maintenance during stage 2 fault handling is duplicated >> between normal pages and PMD hugepages. >> >> Instead of creating another copy of the operations when we introduce >> PUD hugepages, let's share them across the different pagesizes. >> >> Signed-off-by: Punit Agrawal >> Reviewed-by: Christoffer Dall >> Cc: Marc Zyngier >> --- >> virt/kvm/arm/mmu.c | 66 +++++++++++++++++++++++++++------------------- >> 1 file changed, 39 insertions(+), 27 deletions(-) >> >> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c >> index 7f6a944db23d..686fc6a4b866 100644 >> --- a/virt/kvm/arm/mmu.c >> +++ b/virt/kvm/arm/mmu.c [...] >> @@ -1517,28 +1533,34 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> if (mmu_notifier_retry(kvm, mmu_seq)) >> goto out_unlock; >> >> - if (!hugetlb && !force_pte) >> + if (!hugetlb && !force_pte) { >> hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); >> + /* >> + * Only PMD_SIZE transparent hugepages(THP) are >> + * currently supported. This code will need to be >> + * updated to support other THP sizes. >> + */ >> + if (hugetlb) >> + vma_pagesize = PMD_SIZE; > > nit: this is a bit of a trap waiting to happen, as the suggested > semantics of hugetlb is now hugetlbfs and not THP. > > It may be slightly nicer to do do: > > if (transparent_hugepage_adjust(&pfn, &fault_ipa)) > vma_pagesize = PMD_SIZE; I should've noticed this. I'll incorporate your suggestion and update the condition below using hugetlb to rely on vma_pagesize instead. Thanks, Punit > >> + } >> + >> + if (writable) >> + kvm_set_pfn_dirty(pfn); >> + >> + if (fault_status != FSC_PERM) >> + clean_dcache_guest_page(pfn, vma_pagesize); >> + >> + if (exec_fault) >> + invalidate_icache_guest_page(pfn, vma_pagesize); >> >> if (hugetlb) { >> pmd_t new_pmd = pfn_pmd(pfn, mem_type); >> new_pmd = pmd_mkhuge(new_pmd); >> - if (writable) { >> + if (writable) >> new_pmd = kvm_s2pmd_mkwrite(new_pmd); >> - kvm_set_pfn_dirty(pfn); >> - } >> >> - if (fault_status != FSC_PERM) >> - clean_dcache_guest_page(pfn, PMD_SIZE); >> - >> - if (exec_fault) { >> + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) >> new_pmd = kvm_s2pmd_mkexec(new_pmd); >> - invalidate_icache_guest_page(pfn, PMD_SIZE); >> - } else if (fault_status == FSC_PERM) { >> - /* Preserve execute if XN was already cleared */ >> - if (stage2_is_exec(kvm, fault_ipa)) >> - new_pmd = kvm_s2pmd_mkexec(new_pmd); >> - } >> >> ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); >> } else { >> @@ -1546,21 +1568,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> >> if (writable) { >> new_pte = kvm_s2pte_mkwrite(new_pte); >> - kvm_set_pfn_dirty(pfn); >> mark_page_dirty(kvm, gfn); >> } >> >> - if (fault_status != FSC_PERM) >> - clean_dcache_guest_page(pfn, PAGE_SIZE); >> - >> - if (exec_fault) { >> + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) >> new_pte = kvm_s2pte_mkexec(new_pte); >> - invalidate_icache_guest_page(pfn, PAGE_SIZE); >> - } else if (fault_status == FSC_PERM) { >> - /* Preserve execute if XN was already cleared */ >> - if (stage2_is_exec(kvm, fault_ipa)) >> - new_pte = kvm_s2pte_mkexec(new_pte); >> - } >> >> ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags); >> } >> -- >> 2.17.0 >> > > Otherwise looks good. > > Thanks, > -Christoffer > _______________________________________________ > kvmarm mailing list > kvmarm at lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm