From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: "James Hogan" <jhogan@kernel.org>,
"Christian Borntraeger" <borntraeger@de.ibm.com>,
"Janosch Frank" <frankja@linux.ibm.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Marc Zyngier" <marc.zyngier@arm.com>,
"David Hildenbrand" <david@redhat.com>,
"Cornelia Huck" <cohuck@redhat.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
"Joerg Roedel" <joro@8bytes.org>,
"James Morse" <james.morse@arm.com>,
"Julien Thierry" <julien.thierry@arm.com>,
"Suzuki K Pouloze" <suzuki.poulose@arm.com>,
linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org,
kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/13] KVM: Provide common implementation for generic dirty log functions
Date: Thu, 19 Sep 2019 12:39:15 -0700 [thread overview]
Message-ID: <20190919193915.GC30495@linux.intel.com> (raw)
In-Reply-To: <20190919002242.GA19503@blackberry>
On Thu, Sep 19, 2019 at 10:22:42AM +1000, Paul Mackerras wrote:
> On Wed, Sep 11, 2019 at 11:50:35AM -0700, Sean Christopherson wrote:
> > Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG
> > for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code.
> > The arch specific implemenations are extremely similar, differing
> > only in whether the dirty log needs to be sync'd from hardware (x86)
> > and how the TLBs are flushed. Add new arch hooks to handle sync
> > and TLB flush; the sync will also be used for non-generic dirty log
> > support in a future patch (s390).
> >
> > The ulterior motive for providing a common implementation is to
> > eliminate the dependency between arch and common code with respect to
> > the memslot referenced by the dirty log, i.e. to make it obvious in the
> > code that the validity of the memslot is guaranteed, as a future patch
> > will rework memslot handling such that id_to_memslot() can return NULL.
>
> I notice you add empty definitions of kvm_arch_sync_dirty_log() for
> PPC, both Book E and Book 3S. Given that PPC doesn't select
> CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT, why is this necessary?
s390 has a non-empty kvm_arch_sync_dirty_log() but doesn't select
CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT. Patch 11/13 moves s390's call
of kvm_arch_sync_dirty_log() from s390's kvm_vm_ioctl_get_dirty_log() into
the common (but not "generic") kvm_get_dirty_log() so that it's obvious
that kvm_vm_ioctl_get_dirty_log() and kvm_get_dirty_log() are operating on
the same memslot, i.e. aren't independently querying id_to_memslot().
I originally made kvm_arch_sync_dirty_log() opt-in with a __KVM_HAVE_ARCH
macro, but the resulting #ifdeffery felt uglier than having PPC and ARM
provide empty functions.
next prev parent reply other threads:[~2019-09-19 19:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 18:50 [PATCH 00/13] KVM: Dynamically size memslot arrays Sean Christopherson
2019-09-11 18:50 ` [PATCH 01/13] KVM: Reinstall old memslots if arch preparation fails Sean Christopherson
2019-09-11 18:50 ` [PATCH 02/13] KVM: PPC: Move memslot memory allocation into prepare_memory_region() Sean Christopherson
2019-09-19 0:23 ` Paul Mackerras
2019-09-11 18:50 ` [PATCH 03/13] KVM: x86: Allocate memslot resources during prepare_memory_region() Sean Christopherson
2019-09-11 18:50 ` [PATCH 04/13] KVM: Drop kvm_arch_create_memslot() Sean Christopherson
2019-09-12 11:31 ` Janosch Frank
2019-09-11 18:50 ` [PATCH 05/13] KVM: Refactor error handling for setting memory region Sean Christopherson
2019-09-12 11:36 ` Janosch Frank
2019-09-11 18:50 ` [PATCH 06/13] KVM: Move setting of memslot into helper routine Sean Christopherson
2019-09-11 18:50 ` [PATCH 07/13] KVM: Move memslot deletion to helper function Sean Christopherson
2019-09-11 18:50 ` [PATCH 08/13] KVM: Simplify kvm_free_memslot() and all its descendents Sean Christopherson
2019-09-11 18:50 ` [PATCH 09/13] KVM: Clean up local variable usage in __kvm_set_memory_region() Sean Christopherson
2019-09-11 18:50 ` [PATCH 10/13] KVM: Provide common implementation for generic dirty log functions Sean Christopherson
2019-09-19 0:22 ` Paul Mackerras
2019-09-19 19:39 ` Sean Christopherson [this message]
2019-09-11 18:50 ` [PATCH 11/13] KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() Sean Christopherson
2019-09-11 18:50 ` [PATCH 12/13] KVM: Terminate memslot walks via used_slots Sean Christopherson
2019-09-11 18:50 ` [PATCH 13/13] KVM: Dynamically size memslot array based on number of used slots Sean Christopherson
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