From: Paolo Bonzini <pbonzini@redhat.com>
To: Ben Gardon <bgardon@google.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Peter Xu <peterx@redhat.com>,
Sean Christopherson <seanjc@google.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 10/24] kvm: x86/mmu: Factor out handle disconnected pt
Date: Tue, 26 Jan 2021 15:14:16 +0100 [thread overview]
Message-ID: <47e0b040-f9de-376d-80a3-75b5680a7b85@redhat.com> (raw)
In-Reply-To: <20210112181041.356734-11-bgardon@google.com>
On 12/01/21 19:10, Ben Gardon wrote:
> Factor out the code to handle a disconnected subtree of the TDP paging
> structure from the code to handle the change to an individual SPTE.
> Future commits will build on this to allow asynchronous page freeing.
>
> No functional change intended.
>
> Reviewed-by: Peter Feiner <pfeiner@google.com>
>
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 75 +++++++++++++++++++++++---------------
> 1 file changed, 46 insertions(+), 29 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 55df596696c7..e8f35cd46b4c 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -234,6 +234,49 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
> }
> }
>
> +/**
> + * handle_disconnected_tdp_mmu_page - handle a pt removed from the TDP structure
> + *
> + * @kvm: kvm instance
> + * @pt: the page removed from the paging structure
> + *
> + * Given a page table that has been removed from the TDP paging structure,
> + * iterates through the page table to clear SPTEs and free child page tables.
> + */
> +static void handle_disconnected_tdp_mmu_page(struct kvm *kvm, u64 *pt)
> +{
> + struct kvm_mmu_page *sp;
> + gfn_t gfn;
> + int level;
> + u64 old_child_spte;
> + int i;
> +
> + sp = sptep_to_sp(pt);
> + gfn = sp->gfn;
> + level = sp->role.level;
> +
> + trace_kvm_mmu_prepare_zap_page(sp);
> +
> + list_del(&sp->link);
> +
> + if (sp->lpage_disallowed)
> + unaccount_huge_nx_page(kvm, sp);
> +
> + for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
> + old_child_spte = READ_ONCE(*(pt + i));
> + WRITE_ONCE(*(pt + i), 0);
> + handle_changed_spte(kvm, kvm_mmu_page_as_id(sp),
> + gfn + (i * KVM_PAGES_PER_HPAGE(level - 1)),
> + old_child_spte, 0, level - 1);
> + }
> +
> + kvm_flush_remote_tlbs_with_address(kvm, gfn,
> + KVM_PAGES_PER_HPAGE(level));
> +
> + free_page((unsigned long)pt);
> + kmem_cache_free(mmu_page_header_cache, sp);
> +}
> +
> /**
> * handle_changed_spte - handle bookkeeping associated with an SPTE change
> * @kvm: kvm instance
> @@ -254,10 +297,6 @@ static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
> bool was_leaf = was_present && is_last_spte(old_spte, level);
> bool is_leaf = is_present && is_last_spte(new_spte, level);
> bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte);
> - u64 *pt;
> - struct kvm_mmu_page *sp;
> - u64 old_child_spte;
> - int i;
>
> WARN_ON(level > PT64_ROOT_MAX_LEVEL);
> WARN_ON(level < PG_LEVEL_4K);
> @@ -321,31 +360,9 @@ static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
> * Recursively handle child PTs if the change removed a subtree from
> * the paging structure.
> */
> - if (was_present && !was_leaf && (pfn_changed || !is_present)) {
> - pt = spte_to_child_pt(old_spte, level);
> - sp = sptep_to_sp(pt);
> -
> - trace_kvm_mmu_prepare_zap_page(sp);
> -
> - list_del(&sp->link);
> -
> - if (sp->lpage_disallowed)
> - unaccount_huge_nx_page(kvm, sp);
> -
> - for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
> - old_child_spte = READ_ONCE(*(pt + i));
> - WRITE_ONCE(*(pt + i), 0);
> - handle_changed_spte(kvm, as_id,
> - gfn + (i * KVM_PAGES_PER_HPAGE(level - 1)),
> - old_child_spte, 0, level - 1);
> - }
> -
> - kvm_flush_remote_tlbs_with_address(kvm, gfn,
> - KVM_PAGES_PER_HPAGE(level));
> -
> - free_page((unsigned long)pt);
> - kmem_cache_free(mmu_page_header_cache, sp);
> - }
> + if (was_present && !was_leaf && (pfn_changed || !is_present))
> + handle_disconnected_tdp_mmu_page(kvm,
> + spte_to_child_pt(old_spte, level));
> }
>
> static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
>
Queued, thanks.
Paolo
next prev parent reply other threads:[~2021-01-26 14:22 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 18:10 [PATCH 00/24] Allow parallel page faults with TDP MMU Ben Gardon
2021-01-12 18:10 ` [PATCH 01/24] locking/rwlocks: Add contention detection for rwlocks Ben Gardon
2021-01-12 18:10 ` [PATCH 02/24] sched: Add needbreak " Ben Gardon
2021-01-12 18:10 ` [PATCH 03/24] sched: Add cond_resched_rwlock Ben Gardon
2021-01-12 18:10 ` [PATCH 04/24] kvm: x86/mmu: change TDP MMU yield function returns to match cond_resched Ben Gardon
2021-01-20 18:38 ` Sean Christopherson
2021-01-21 20:22 ` Paolo Bonzini
2021-01-26 14:11 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 05/24] kvm: x86/mmu: Fix yielding in TDP MMU Ben Gardon
2021-01-20 19:28 ` Sean Christopherson
2021-01-22 1:06 ` Ben Gardon
2021-01-12 18:10 ` [PATCH 06/24] kvm: x86/mmu: Skip no-op changes in TDP MMU functions Ben Gardon
2021-01-20 19:51 ` Sean Christopherson
2021-01-25 23:51 ` Ben Gardon
2021-01-12 18:10 ` [PATCH 07/24] kvm: x86/mmu: Add comment on __tdp_mmu_set_spte Ben Gardon
2021-01-26 14:13 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 08/24] kvm: x86/mmu: Add lockdep when setting a TDP MMU SPTE Ben Gardon
2021-01-20 19:58 ` Sean Christopherson
2021-01-26 14:13 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 09/24] kvm: x86/mmu: Don't redundantly clear TDP MMU pt memory Ben Gardon
2021-01-20 20:06 ` Sean Christopherson
2021-01-26 14:14 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 10/24] kvm: x86/mmu: Factor out handle disconnected pt Ben Gardon
2021-01-20 20:30 ` Sean Christopherson
2021-01-26 14:14 ` Paolo Bonzini [this message]
2021-01-12 18:10 ` [PATCH 11/24] kvm: x86/mmu: Put TDP MMU PT walks in RCU read-critical section Ben Gardon
2021-01-20 22:19 ` Sean Christopherson
2021-01-12 18:10 ` [PATCH 12/24] kvm: x86/kvm: RCU dereference tdp mmu page table links Ben Gardon
2021-01-22 18:32 ` Sean Christopherson
2021-01-26 18:17 ` Ben Gardon
2021-01-12 18:10 ` [PATCH 13/24] kvm: x86/mmu: Only free tdp_mmu pages after a grace period Ben Gardon
2021-01-12 18:10 ` [PATCH 14/24] kvm: mmu: Wrap mmu_lock lock / unlock in a function Ben Gardon
2021-01-12 18:10 ` [PATCH 15/24] kvm: mmu: Wrap mmu_lock cond_resched and needbreak Ben Gardon
2021-01-21 0:19 ` Sean Christopherson
2021-01-21 20:17 ` Paolo Bonzini
2021-01-26 14:38 ` Paolo Bonzini
2021-01-26 17:47 ` Ben Gardon
2021-01-26 17:55 ` Paolo Bonzini
2021-01-26 18:11 ` Ben Gardon
2021-01-26 20:47 ` Paolo Bonzini
2021-01-27 20:08 ` Ben Gardon
2021-01-27 20:55 ` Paolo Bonzini
2021-01-27 21:20 ` Ben Gardon
2021-01-28 8:18 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 16/24] kvm: mmu: Wrap mmu_lock assertions Ben Gardon
2021-01-26 14:29 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 17/24] kvm: mmu: Move mmu_lock to struct kvm_arch Ben Gardon
2021-01-12 18:10 ` [PATCH 18/24] kvm: x86/mmu: Use an rwlock for the x86 TDP MMU Ben Gardon
2021-01-21 0:45 ` Sean Christopherson
2021-01-12 18:10 ` [PATCH 19/24] kvm: x86/mmu: Protect tdp_mmu_pages with a lock Ben Gardon
2021-01-21 19:22 ` Sean Christopherson
2021-01-21 21:32 ` Sean Christopherson
2021-01-26 14:27 ` Paolo Bonzini
2021-01-26 21:47 ` Ben Gardon
2021-01-26 22:02 ` Sean Christopherson
2021-01-26 22:09 ` Sean Christopherson
2021-01-27 12:40 ` Paolo Bonzini
2021-01-26 13:37 ` Paolo Bonzini
2021-01-26 21:07 ` Ben Gardon
2021-01-12 18:10 ` [PATCH 20/24] kvm: x86/mmu: Add atomic option for setting SPTEs Ben Gardon
2021-01-26 14:21 ` Paolo Bonzini
2021-01-12 18:10 ` [PATCH 21/24] kvm: x86/mmu: Use atomic ops to set SPTEs in TDP MMU map Ben Gardon
2021-01-12 18:10 ` [PATCH 22/24] kvm: x86/mmu: Flush TLBs after zap in TDP MMU PF handler Ben Gardon
2021-01-21 0:05 ` Sean Christopherson
2021-01-12 18:10 ` [PATCH 23/24] kvm: x86/mmu: Freeze SPTEs in disconnected pages Ben Gardon
2021-01-12 18:10 ` [PATCH 24/24] kvm: x86/mmu: Allow parallel page faults for the TDP MMU Ben Gardon
2021-01-21 0:55 ` Sean Christopherson
2021-01-26 21:57 ` Ben Gardon
2021-01-27 17:14 ` Sean Christopherson
2021-01-26 13:37 ` Paolo Bonzini
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