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From: Paolo Bonzini <pbonzini@redhat.com>
To: Ben Gardon <bgardon@google.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Cannon Matthews <cannonmatthews@google.com>,
	Peter Xu <peterx@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Peter Shier <pshier@google.com>,
	Peter Feiner <pfeiner@google.com>,
	Junaid Shahid <junaids@google.com>,
	Jim Mattson <jmattson@google.com>,
	Yulei Zhang <yulei.kernel@gmail.com>,
	Wanpeng Li <kernellwp@gmail.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Xiao Guangrong <xiaoguangrong.eric@gmail.com>
Subject: Re: [PATCH 17/22] kvm: mmu: Support dirty logging for the TDP MMU
Date: Sat, 26 Sep 2020 03:04:47 +0200	[thread overview]
Message-ID: <6990180c-f99c-3f1d-ef6a-57e37a9999d2@redhat.com> (raw)
In-Reply-To: <20200925212302.3979661-18-bgardon@google.com>

On 25/09/20 23:22, Ben Gardon wrote:
>  				start_level, KVM_MAX_HUGEPAGE_LEVEL, false);
> +	if (kvm->arch.tdp_mmu_enabled)
> +		flush = kvm_tdp_mmu_wrprot_slot(kvm, memslot, false) || flush;
>  	spin_unlock(&kvm->mmu_lock);
>  

In fact you can just pass down the end-level KVM_MAX_HUGEPAGE_LEVEL or
PGLEVEL_4K here to kvm_tdp_mmu_wrprot_slot and from there to
wrprot_gfn_range.

> 
> +		/*
> +		 * Take a reference on the root so that it cannot be freed if
> +		 * this thread releases the MMU lock and yields in this loop.
> +		 */
> +		get_tdp_mmu_root(kvm, root);
> +
> +		spte_set = wrprot_gfn_range(kvm, root, slot->base_gfn,
> +				slot->base_gfn + slot->npages, skip_4k) ||
> +			   spte_set;
> +
> +		put_tdp_mmu_root(kvm, root);


Generalyl using "|=" is the more common idiom in mmu.c.

> +static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
> +			   gfn_t start, gfn_t end)
> ...
> +		__handle_changed_spte(kvm, as_id, iter.gfn, iter.old_spte,
> +				      new_spte, iter.level);
> +		handle_changed_spte_acc_track(iter.old_spte, new_spte,
> +					      iter.level);

Is it worth not calling handle_changed_spte?  handle_changed_spte_dlog
obviously will never fire but duplicating the code is a bit ugly.

I guess this patch is the first one that really gives the "feeling" of
what the data structures look like.  The main difference with the shadow
MMU is that you have the tdp_iter instead of the callback-based code of
slot_handle_level_range, but otherwise it's not hard to follow one if
you know the other.  Reorganizing the code so that mmu.c is little more
than a wrapper around the two will help as well in this respect.

Paolo


  reply	other threads:[~2020-09-26  1:04 UTC|newest]

Thread overview: 111+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 21:22 [PATCH 00/22] Introduce the TDP MMU Ben Gardon
2020-09-25 21:22 ` [PATCH 01/22] kvm: mmu: Separate making SPTEs from set_spte Ben Gardon
2020-09-30  4:55   ` Sean Christopherson
2020-09-30 23:03     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 02/22] kvm: mmu: Introduce tdp_iter Ben Gardon
2020-09-26  0:04   ` Paolo Bonzini
2020-09-30  5:06     ` Sean Christopherson
2020-09-26  0:54   ` Paolo Bonzini
2020-09-30  5:08   ` Sean Christopherson
2020-09-30  5:24   ` Sean Christopherson
2020-09-30  6:24     ` Paolo Bonzini
2020-09-30 23:20   ` Eric van Tassell
2020-09-30 23:34     ` Paolo Bonzini
2020-10-01  0:07       ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 03/22] kvm: mmu: Init / Uninit the TDP MMU Ben Gardon
2020-09-26  0:06   ` Paolo Bonzini
2020-09-30  5:34   ` Sean Christopherson
2020-09-30 18:36     ` Ben Gardon
2020-09-30 16:57   ` Sean Christopherson
2020-09-30 17:39     ` Paolo Bonzini
2020-09-30 18:42       ` Ben Gardon
2020-09-25 21:22 ` [PATCH 04/22] kvm: mmu: Allocate and free TDP MMU roots Ben Gardon
2020-09-30  6:06   ` Sean Christopherson
2020-09-30  6:26     ` Paolo Bonzini
2020-09-30 15:38       ` Sean Christopherson
2020-10-12 22:59     ` Ben Gardon
2020-10-12 23:59       ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 05/22] kvm: mmu: Add functions to handle changed TDP SPTEs Ben Gardon
2020-09-26  0:39   ` Paolo Bonzini
2020-09-28 17:23     ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 06/22] kvm: mmu: Make address space ID a property of memslots Ben Gardon
2020-09-30  6:10   ` Sean Christopherson
2020-09-30 23:11     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 07/22] kvm: mmu: Support zapping SPTEs in the TDP MMU Ben Gardon
2020-09-26  0:14   ` Paolo Bonzini
2020-09-30  6:15   ` Sean Christopherson
2020-09-30  6:28     ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 08/22] kvm: mmu: Separate making non-leaf sptes from link_shadow_page Ben Gardon
2020-09-25 21:22 ` [PATCH 09/22] kvm: mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg Ben Gardon
2020-09-30 16:19   ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 10/22] kvm: mmu: Add TDP MMU PF handler Ben Gardon
2020-09-26  0:24   ` Paolo Bonzini
2020-09-30 16:37   ` Sean Christopherson
2020-09-30 16:55     ` Paolo Bonzini
2020-09-30 17:37     ` Paolo Bonzini
2020-10-06 22:35       ` Ben Gardon
2020-10-06 22:33     ` Ben Gardon
2020-10-07 20:55       ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 11/22] kvm: mmu: Factor out allocating a new tdp_mmu_page Ben Gardon
2020-09-26  0:22   ` Paolo Bonzini
2020-09-30 18:53     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 12/22] kvm: mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU Ben Gardon
2020-09-25 21:22 ` [PATCH 13/22] kvm: mmu: Support invalidate range MMU notifier for " Ben Gardon
2020-09-30 17:03   ` Sean Christopherson
2020-09-30 23:15     ` Ben Gardon
2020-09-30 23:24       ` Sean Christopherson
2020-09-30 23:27         ` Ben Gardon
2020-09-25 21:22 ` [PATCH 14/22] kvm: mmu: Add access tracking for tdp_mmu Ben Gardon
2020-09-26  0:32   ` Paolo Bonzini
2020-09-30 17:48   ` Sean Christopherson
2020-10-06 23:38     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 15/22] kvm: mmu: Support changed pte notifier in tdp MMU Ben Gardon
2020-09-26  0:33   ` Paolo Bonzini
2020-09-28 15:11   ` Paolo Bonzini
2020-10-07 16:53     ` Ben Gardon
2020-10-07 17:18       ` Paolo Bonzini
2020-10-07 17:30         ` Ben Gardon
2020-10-07 17:54           ` Paolo Bonzini
2020-10-09 10:59   ` Dan Carpenter
2020-10-09 10:59     ` Dan Carpenter
2020-09-25 21:22 ` [PATCH 16/22] kvm: mmu: Add dirty logging handler for changed sptes Ben Gardon
2020-09-26  0:45   ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 17/22] kvm: mmu: Support dirty logging for the TDP MMU Ben Gardon
2020-09-26  1:04   ` Paolo Bonzini [this message]
2020-10-08 18:27     ` Ben Gardon
2020-09-29 15:07   ` Paolo Bonzini
2020-09-30 18:04   ` Sean Christopherson
2020-09-30 18:08     ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 18/22] kvm: mmu: Support disabling dirty logging for the tdp MMU Ben Gardon
2020-09-26  1:09   ` Paolo Bonzini
2020-10-07 16:30     ` Ben Gardon
2020-10-07 17:21       ` Paolo Bonzini
2020-10-07 17:28         ` Ben Gardon
2020-10-07 17:53           ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 19/22] kvm: mmu: Support write protection for nesting in " Ben Gardon
2020-09-30 18:06   ` Sean Christopherson
2020-09-25 21:23 ` [PATCH 20/22] kvm: mmu: NX largepage recovery for TDP MMU Ben Gardon
2020-09-26  1:14   ` Paolo Bonzini
2020-09-30 22:23     ` Ben Gardon
2020-09-29 18:24   ` Paolo Bonzini
2020-09-30 18:15   ` Sean Christopherson
2020-09-30 19:56     ` Paolo Bonzini
2020-09-30 22:33       ` Ben Gardon
2020-09-30 22:27     ` Ben Gardon
2020-10-09 11:03   ` Dan Carpenter
2020-10-09 11:03     ` Dan Carpenter
2020-09-25 21:23 ` [PATCH 21/22] kvm: mmu: Support MMIO in the " Ben Gardon
2020-09-30 18:19   ` Sean Christopherson
2020-10-09 11:43   ` Dan Carpenter
2020-10-09 11:43     ` Dan Carpenter
2020-09-25 21:23 ` [PATCH 22/22] kvm: mmu: Don't clear write flooding count for direct roots Ben Gardon
2020-09-26  1:25   ` Paolo Bonzini
2020-10-05 22:48     ` Ben Gardon
2020-10-05 23:44       ` Sean Christopherson
2020-10-06 16:19         ` Ben Gardon
2020-09-26  1:14 ` [PATCH 00/22] Introduce the TDP MMU Paolo Bonzini
2020-09-28 17:31 ` Paolo Bonzini
2020-09-29 17:40   ` Ben Gardon
2020-09-29 18:10     ` Paolo Bonzini
2020-09-30  6:19 ` Sean Christopherson
2020-09-30  6:30   ` Paolo Bonzini

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