From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paul Mackerras <paulus@ozlabs.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu,
syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com,
Andrea Arcangeli <aarcange@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Barret Rhoden <brho@google.com>,
David Hildenbrand <david@redhat.com>,
Jason Zeng <jason.zeng@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Liran Alon <liran.alon@oracle.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH 04/14] KVM: Play nice with read-only memslots when querying host page size
Date: Tue, 21 Jan 2020 15:24:29 +0100 [thread overview]
Message-ID: <2c091d40-8e32-1e55-2eff-27a4b43e0674@redhat.com> (raw)
In-Reply-To: <20200108202448.9669-5-sean.j.christopherson@intel.com>
On 08/01/20 21:24, Sean Christopherson wrote:
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 5f7f06824c2b..d9aced677ddd 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1418,15 +1418,23 @@ EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
>
> unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
> {
> + struct kvm_memory_slot *slot;
> struct vm_area_struct *vma;
> unsigned long addr, size;
>
> size = PAGE_SIZE;
>
> - addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
> - if (kvm_is_error_hva(addr))
> + /*
> + * Manually do the equivalent of kvm_vcpu_gfn_to_hva() to avoid the
> + * "writable" check in __gfn_to_hva_many(), which will always fail on
> + * read-only memslots due to gfn_to_hva() assuming writes.
> + */
> + slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
> + if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
> return PAGE_SIZE;
>
> + addr = __gfn_to_hva_memslot(slot, gfn);
> +
> down_read(¤t->mm->mmap_sem);
> vma = find_vma(current->mm, addr);
> if (!vma)
>
Even simpler: use kvm_vcpu_gfn_to_hva_prot
- addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
+ addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
"You are in a maze of twisty little functions, all alike".
Paolo
next prev parent reply other threads:[~2020-01-21 14:24 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 20:24 [PATCH 00/14] KVM: x86/mmu: Huge page fixes, cleanup, and DAX Sean Christopherson
2020-01-08 20:24 ` [PATCH 01/14] KVM: x86/mmu: Enforce max_level on HugeTLB mappings Sean Christopherson
2020-01-08 20:24 ` [PATCH 02/14] mm: thp: KVM: Explicitly check for THP when populating secondary MMU Sean Christopherson
2020-01-08 20:24 ` [PATCH 03/14] KVM: Use vcpu-specific gva->hva translation when querying host page size Sean Christopherson
2020-01-08 20:24 ` [PATCH 04/14] KVM: Play nice with read-only memslots " Sean Christopherson
2020-01-21 14:24 ` Paolo Bonzini [this message]
2020-01-08 20:24 ` [PATCH 05/14] x86/mm: Introduce lookup_address_in_mm() Sean Christopherson
2020-01-09 21:04 ` Thomas Gleixner
2020-01-21 14:26 ` Paolo Bonzini
2020-01-08 20:24 ` [PATCH 06/14] KVM: x86/mmu: Refactor THP adjust to prep for changing query Sean Christopherson
2020-01-08 20:24 ` [PATCH 07/14] KVM: x86/mmu: Walk host page tables to find THP mappings Sean Christopherson
2020-01-21 14:40 ` Paolo Bonzini
2020-01-08 20:24 ` [PATCH 08/14] KVM: x86/mmu: Drop level optimization from fast_page_fault() Sean Christopherson
2020-01-08 20:24 ` [PATCH 09/14] KVM: x86/mmu: Rely on host page tables to find HugeTLB mappings Sean Christopherson
2020-01-08 20:24 ` [PATCH 10/14] KVM: x86/mmu: Remove obsolete gfn restoration in FNAME(fetch) Sean Christopherson
2020-01-08 20:24 ` [PATCH 11/14] KVM: x86/mmu: Zap any compound page when collapsing sptes Sean Christopherson
2020-01-08 20:24 ` [PATCH 12/14] KVM: x86/mmu: Fold max_mapping_level() into kvm_mmu_hugepage_adjust() Sean Christopherson
2020-01-21 15:12 ` Paolo Bonzini
2020-01-08 20:24 ` [PATCH 13/14] KVM: x86/mmu: Remove lpage_is_disallowed() check from set_spte() Sean Christopherson
2020-01-08 20:24 ` [PATCH 14/14] KVM: x86/mmu: Use huge pages for DAX-backed files Sean Christopherson
2020-01-09 19:47 ` [PATCH 00/14] KVM: x86/mmu: Huge page fixes, cleanup, and DAX Barret Rhoden
2020-01-21 15:10 ` Paolo Bonzini
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