Linux-MIPS Archive on lore.kernel.org
 help / color / Atom feed
From: Peter Xu <peterx@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Paul Mackerras" <paulus@ozlabs.org>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Janosch Frank" <frankja@linux.ibm.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>, "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>,
	linux-mips@vger.kernel.org, kvm@vger.kernel.org,
	kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
	"Christoffer Dall" <christoffer.dall@arm.com>,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>
Subject: Re: [PATCH v5 09/19] KVM: Move setting of memslot into helper routine
Date: Thu, 6 Feb 2020 11:26:17 -0500
Message-ID: <20200206162617.GB695333@xz-x1> (raw)
In-Reply-To: <20200121223157.15263-10-sean.j.christopherson@intel.com>

On Tue, Jan 21, 2020 at 02:31:47PM -0800, Sean Christopherson wrote:
> Split out the core functionality of setting a memslot into a separate
> helper in preparation for moving memslot deletion into its own routine.
> 
> Tested-by: Christoffer Dall <christoffer.dall@arm.com>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  virt/kvm/kvm_main.c | 106 ++++++++++++++++++++++++++------------------
>  1 file changed, 63 insertions(+), 43 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index fdf045a5d240..64f6c5d35260 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -982,6 +982,66 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
>  	return old_memslots;
>  }
>  
> +static int kvm_set_memslot(struct kvm *kvm,
> +			   const struct kvm_userspace_memory_region *mem,
> +			   const struct kvm_memory_slot *old,
> +			   struct kvm_memory_slot *new, int as_id,
> +			   enum kvm_mr_change change)
> +{
> +	struct kvm_memory_slot *slot;
> +	struct kvm_memslots *slots;
> +	int r;
> +
> +	slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
> +	if (!slots)
> +		return -ENOMEM;
> +	memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
> +
> +	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
> +		/*
> +		 * Note, the INVALID flag needs to be in the appropriate entry
> +		 * in the freshly allocated memslots, not in @old or @new.
> +		 */
> +		slot = id_to_memslot(slots, old->id);
> +		slot->flags |= KVM_MEMSLOT_INVALID;
> +
> +		/*
> +		 * We can re-use the old memslots, the only difference from the
> +		 * newly installed memslots is the invalid flag, which will get
> +		 * dropped by update_memslots anyway.  We'll also revert to the
> +		 * old memslots if preparing the new memory region fails.
> +		 */
> +		slots = install_new_memslots(kvm, as_id, slots);
> +
> +		/* From this point no new shadow pages pointing to a deleted,
> +		 * or moved, memslot will be created.
> +		 *
> +		 * validation of sp->gfn happens in:
> +		 *	- gfn_to_hva (kvm_read_guest, gfn_to_pfn)
> +		 *	- kvm_is_visible_gfn (mmu_check_root)
> +		 */
> +		kvm_arch_flush_shadow_memslot(kvm, slot);
> +	}
> +
> +	r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
> +	if (r)
> +		goto out_slots;
> +
> +	update_memslots(slots, new, change);
> +	slots = install_new_memslots(kvm, as_id, slots);
> +
> +	kvm_arch_commit_memory_region(kvm, mem, old, new, change);
> +
> +	kvfree(slots);
> +	return 0;
> +
> +out_slots:
> +	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
> +		slots = install_new_memslots(kvm, as_id, slots);
> +	kvfree(slots);
> +	return r;
> +}
> +
>  /*
>   * Allocate some memory and give it an address in the guest physical address
>   * space.
> @@ -998,7 +1058,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
>  	unsigned long npages;
>  	struct kvm_memory_slot *slot;
>  	struct kvm_memory_slot old, new;
> -	struct kvm_memslots *slots;
>  	int as_id, id;
>  	enum kvm_mr_change change;
>  
> @@ -1085,58 +1144,19 @@ int __kvm_set_memory_region(struct kvm *kvm,
>  			return r;
>  	}
>  
> -	slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
> -	if (!slots) {
> -		r = -ENOMEM;
> -		goto out_bitmap;
> -	}
> -	memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
> -
> -	if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
> -		slot = id_to_memslot(slots, id);
> -		slot->flags |= KVM_MEMSLOT_INVALID;
> -
> -		/*
> -		 * We can re-use the old memslots, the only difference from the
> -		 * newly installed memslots is the invalid flag, which will get
> -		 * dropped by update_memslots anyway.  We'll also revert to the
> -		 * old memslots if preparing the new memory region fails.
> -		 */
> -		slots = install_new_memslots(kvm, as_id, slots);
> -
> -		/* From this point no new shadow pages pointing to a deleted,
> -		 * or moved, memslot will be created.
> -		 *
> -		 * validation of sp->gfn happens in:
> -		 *	- gfn_to_hva (kvm_read_guest, gfn_to_pfn)
> -		 *	- kvm_is_visible_gfn (mmu_check_root)
> -		 */
> -		kvm_arch_flush_shadow_memslot(kvm, slot);
> -	}
> -
> -	r = kvm_arch_prepare_memory_region(kvm, &new, mem, change);
> -	if (r)
> -		goto out_slots;
> -
>  	/* actual memory is freed via old in kvm_free_memslot below */
>  	if (change == KVM_MR_DELETE) {
>  		new.dirty_bitmap = NULL;
>  		memset(&new.arch, 0, sizeof(new.arch));
>  	}

It's not extremely clear to me on why this single block is leftover
here instead of putting into kvm_set_memslot().  I see that after all
it'll be removed in patch 12, so it seems OK:

Reviewed-by: Peter Xu <peterx@redhat.com>

>  
> -	update_memslots(slots, &new, change);
> -	slots = install_new_memslots(kvm, as_id, slots);
> -
> -	kvm_arch_commit_memory_region(kvm, mem, &old, &new, change);
> +	r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change);
> +	if (r)
> +		goto out_bitmap;
>  
>  	kvm_free_memslot(kvm, &old, &new);
> -	kvfree(slots);
>  	return 0;
>  
> -out_slots:
> -	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
> -		slots = install_new_memslots(kvm, as_id, slots);
> -	kvfree(slots);
>  out_bitmap:
>  	if (new.dirty_bitmap && !old.dirty_bitmap)
>  		kvm_destroy_dirty_bitmap(&new);
> -- 
> 2.24.1
> 

-- 
Peter Xu


  reply index

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-21 22:31 [PATCH v5 00/19] KVM: Dynamically size memslot arrays Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 01/19] KVM: x86: Allocate new rmap and large page tracking when moving memslot Sean Christopherson
2020-02-05 21:49   ` Peter Xu
2020-02-05 23:55     ` Sean Christopherson
2020-02-06  2:00       ` Peter Xu
2020-02-06  2:17         ` Sean Christopherson
2020-02-06  2:58           ` Peter Xu
2020-02-06  5:05             ` Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 02/19] KVM: Reinstall old memslots if arch preparation fails Sean Christopherson
2020-02-05 22:08   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 03/19] KVM: Don't free new memslot if allocation of said memslot fails Sean Christopherson
2020-02-05 22:28   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 04/19] KVM: PPC: Move memslot memory allocation into prepare_memory_region() Sean Christopherson
2020-02-05 22:41   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 05/19] KVM: x86: Allocate memslot resources during prepare_memory_region() Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 06/19] KVM: Drop kvm_arch_create_memslot() Sean Christopherson
2020-02-05 22:45   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 07/19] KVM: Explicitly free allocated-but-unused dirty bitmap Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 08/19] KVM: Refactor error handling for setting memory region Sean Christopherson
2020-02-05 22:48   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 09/19] KVM: Move setting of memslot into helper routine Sean Christopherson
2020-02-06 16:26   ` Peter Xu [this message]
2020-01-21 22:31 ` [PATCH v5 10/19] KVM: Drop "const" attribute from old memslot in commit_memory_region() Sean Christopherson
2020-02-06 16:26   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 11/19] KVM: x86: Free arrays for old memslot when moving memslot's base gfn Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 12/19] KVM: Move memslot deletion to helper function Sean Christopherson
2020-02-06 16:14   ` Peter Xu
2020-02-06 16:28     ` Sean Christopherson
2020-02-06 16:51       ` Peter Xu
2020-02-07 17:59         ` Sean Christopherson
2020-02-07 18:07           ` Sean Christopherson
2020-02-07 18:17           ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 13/19] KVM: Simplify kvm_free_memslot() and all its descendents Sean Christopherson
2020-02-06 16:29   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 14/19] KVM: Clean up local variable usage in __kvm_set_memory_region() Sean Christopherson
2020-02-06 19:06   ` Peter Xu
2020-02-06 19:22     ` Sean Christopherson
2020-02-06 19:36       ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 15/19] KVM: Provide common implementation for generic dirty log functions Sean Christopherson
2020-02-06 20:02   ` Peter Xu
2020-02-06 21:21     ` Sean Christopherson
2020-02-06 21:41       ` Peter Xu
2020-02-07 19:45         ` Sean Christopherson
2020-02-08  0:18           ` Peter Xu
2020-02-08  0:42             ` Sean Christopherson
2020-02-08  0:53               ` Peter Xu
2020-02-08  1:29                 ` Sean Christopherson
2020-02-17 15:39                   ` Vitaly Kuznetsov
2020-02-18 17:10                     ` Sean Christopherson
2020-02-17 15:35           ` Vitaly Kuznetsov
2020-02-06 21:24   ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 16/19] KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 17/19] KVM: Terminate memslot walks via used_slots Sean Christopherson
2020-02-06 21:09   ` Peter Xu
2020-02-07 18:33     ` Sean Christopherson
2020-02-07 20:39       ` Peter Xu
2020-02-07 21:10         ` Sean Christopherson
2020-02-07 21:46           ` Peter Xu
2020-02-07 22:03             ` Sean Christopherson
2020-02-07 22:24               ` Peter Xu
2020-01-21 22:31 ` [PATCH v5 18/19] KVM: Dynamically size memslot array based on number of used slots Sean Christopherson
2020-02-06 22:12   ` Peter Xu
2020-02-07 15:38     ` Sean Christopherson
2020-02-07 16:05       ` Peter Xu
2020-02-07 16:15         ` Sean Christopherson
2020-02-07 16:37           ` Peter Xu
2020-02-07 16:47             ` Sean Christopherson
2020-01-21 22:31 ` [PATCH v5 19/19] KVM: selftests: Add test for KVM_SET_USER_MEMORY_REGION Sean Christopherson
2020-02-06 22:30   ` Peter Xu
2020-02-06 23:11     ` Sean Christopherson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200206162617.GB695333@xz-x1 \
    --to=peterx@redhat.com \
    --cc=borntraeger@de.ibm.com \
    --cc=christoffer.dall@arm.com \
    --cc=cohuck@redhat.com \
    --cc=david@redhat.com \
    --cc=f4bug@amsat.org \
    --cc=frankja@linux.ibm.com \
    --cc=james.morse@arm.com \
    --cc=jmattson@google.com \
    --cc=joro@8bytes.org \
    --cc=julien.thierry.kdev@gmail.com \
    --cc=kvm-ppc@vger.kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=paulus@ozlabs.org \
    --cc=pbonzini@redhat.com \
    --cc=sean.j.christopherson@intel.com \
    --cc=suzuki.poulose@arm.com \
    --cc=vkuznets@redhat.com \
    --cc=wanpengli@tencent.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-MIPS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mips/0 linux-mips/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mips linux-mips/ https://lore.kernel.org/linux-mips \
		linux-mips@vger.kernel.org
	public-inbox-index linux-mips

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-mips


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git