From: Sean Christopherson <seanjc@google.com>
To: Anish Moorthy <amoorthy@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
isaku.yamahata@intel.com, binbin.wu@linux.intel.com,
xiaoyao.li@intel.com,
Rick Edgecombe <rick.p.edgecombe@intel.com>
Subject: Re: [PATCH v5 2/7] KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory
Date: Wed, 10 Jul 2024 14:56:30 -0700 [thread overview]
Message-ID: <Zo8DjhQq3GOpmO5f@google.com> (raw)
In-Reply-To: <CAF7b7mogOgTs5FZMfuUDms2uHqy3_CNu7p=3TanLzHkem=EMyA@mail.gmail.com>
On Wed, Jul 10, 2024, Anish Moorthy wrote:
> On Wed, Jul 10, 2024 at 10:41 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > + if (!PAGE_ALIGNED(range->gpa) ||
> > + !PAGE_ALIGNED(range->size) ||
> > ...
> > + return -EINVAL;
>
> If 'gpa' and 'size' must be page-aligned anyways, doesn't it make
> sense to just take a 'gfn' and 'num_pages' and eliminate this error
> condition?
The downside is that taking gfn+num_pages prevents supporting sub-page pre-faulting
in the future. I highly doubt that sub-page mappings will ever be a thing in KVM,
but two PAGE_ALIGNED() checks is super cheap, so it's soft of a "why not?" scenario.
next prev parent reply other threads:[~2024-07-10 21:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-10 17:40 [PATCH v5 0/7] KVM: Guest Memory Pre-Population API Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 1/7] KVM: Document KVM_PRE_FAULT_MEMORY ioctl Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 2/7] KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory Paolo Bonzini
2024-07-10 20:46 ` Anish Moorthy
2024-07-10 21:56 ` Sean Christopherson [this message]
2024-07-10 22:04 ` Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 3/7] KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 4/7] KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault" Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 5/7] KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 6/7] KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory() Paolo Bonzini
2024-07-11 5:36 ` Binbin Wu
2024-07-11 8:30 ` Paolo Bonzini
2024-07-10 17:40 ` [PATCH v5 7/7] KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY Paolo Bonzini
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