From: Ben Gardon <bgardon@google.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>, 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>,
Ben Gardon <bgardon@google.com>
Subject: [PATCH v2 14/28] KVM: x86/mmu: Yield in TDU MMU iter even if no SPTES changed
Date: Tue, 2 Feb 2021 10:57:20 -0800 [thread overview]
Message-ID: <20210202185734.1680553-15-bgardon@google.com> (raw)
In-Reply-To: <20210202185734.1680553-1-bgardon@google.com>
Given certain conditions, some TDP MMU functions may not yield
reliably / frequently enough. For example, if a paging structure was
very large but had few, if any writable entries, wrprot_gfn_range
could traverse many entries before finding a writable entry and yielding
because the check for yielding only happens after an SPTE is modified.
Fix this issue by moving the yield to the beginning of the loop.
Fixes: a6a0b05da9f3 ("kvm: x86/mmu: Support dirty logging for the TDP MMU")
Reviewed-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
---
v1 -> v2
- Split patch into three
arch/x86/kvm/mmu/tdp_mmu.c | 32 ++++++++++++++++++++++----------
1 file changed, 22 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 7cfc0639b1ef..c8a1149cb229 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -501,6 +501,12 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
bool flush_needed = false;
tdp_root_for_each_pte(iter, root, start, end) {
+ if (can_yield &&
+ tdp_mmu_iter_cond_resched(kvm, &iter, flush_needed)) {
+ flush_needed = false;
+ continue;
+ }
+
if (!is_shadow_present_pte(iter.old_spte))
continue;
@@ -515,9 +521,7 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
continue;
tdp_mmu_set_spte(kvm, &iter, 0);
-
- flush_needed = !(can_yield &&
- tdp_mmu_iter_cond_resched(kvm, &iter, true));
+ flush_needed = true;
}
return flush_needed;
}
@@ -880,6 +884,9 @@ static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
for_each_tdp_pte_min_level(iter, root->spt, root->role.level,
min_level, start, end) {
+ if (tdp_mmu_iter_cond_resched(kvm, &iter, false))
+ continue;
+
if (!is_shadow_present_pte(iter.old_spte) ||
!is_last_spte(iter.old_spte, iter.level))
continue;
@@ -888,8 +895,6 @@ static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte);
spte_set = true;
-
- tdp_mmu_iter_cond_resched(kvm, &iter, false);
}
return spte_set;
}
@@ -933,6 +938,9 @@ static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
bool spte_set = false;
tdp_root_for_each_leaf_pte(iter, root, start, end) {
+ if (tdp_mmu_iter_cond_resched(kvm, &iter, false))
+ continue;
+
if (spte_ad_need_write_protect(iter.old_spte)) {
if (is_writable_pte(iter.old_spte))
new_spte = iter.old_spte & ~PT_WRITABLE_MASK;
@@ -947,8 +955,6 @@ static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte);
spte_set = true;
-
- tdp_mmu_iter_cond_resched(kvm, &iter, false);
}
return spte_set;
}
@@ -1056,6 +1062,9 @@ static bool set_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
bool spte_set = false;
tdp_root_for_each_pte(iter, root, start, end) {
+ if (tdp_mmu_iter_cond_resched(kvm, &iter, false))
+ continue;
+
if (!is_shadow_present_pte(iter.old_spte))
continue;
@@ -1063,8 +1072,6 @@ static bool set_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
tdp_mmu_set_spte(kvm, &iter, new_spte);
spte_set = true;
-
- tdp_mmu_iter_cond_resched(kvm, &iter, false);
}
return spte_set;
@@ -1105,6 +1112,11 @@ static void zap_collapsible_spte_range(struct kvm *kvm,
bool spte_set = false;
tdp_root_for_each_pte(iter, root, start, end) {
+ if (tdp_mmu_iter_cond_resched(kvm, &iter, spte_set)) {
+ spte_set = false;
+ continue;
+ }
+
if (!is_shadow_present_pte(iter.old_spte) ||
!is_last_spte(iter.old_spte, iter.level))
continue;
@@ -1116,7 +1128,7 @@ static void zap_collapsible_spte_range(struct kvm *kvm,
tdp_mmu_set_spte(kvm, &iter, 0);
- spte_set = !tdp_mmu_iter_cond_resched(kvm, &iter, true);
+ spte_set = true;
}
if (spte_set)
--
2.30.0.365.g02bc693789-goog
next prev parent reply other threads:[~2021-02-02 19:02 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 18:57 [PATCH v2 00/28] Allow parallel MMU operations with TDP MMU Ben Gardon
2021-02-02 18:57 ` [PATCH v2 01/28] KVM: x86/mmu: change TDP MMU yield function returns to match cond_resched Ben Gardon
2021-02-02 18:57 ` [PATCH v2 02/28] KVM: x86/mmu: Add comment on __tdp_mmu_set_spte Ben Gardon
2021-02-02 18:57 ` [PATCH v2 03/28] KVM: x86/mmu: Add lockdep when setting a TDP MMU SPTE Ben Gardon
2021-02-02 18:57 ` [PATCH v2 04/28] KVM: x86/mmu: Don't redundantly clear TDP MMU pt memory Ben Gardon
2021-02-02 18:57 ` [PATCH v2 05/28] KVM: x86/mmu: Factor out handling of removed page tables Ben Gardon
2021-02-02 18:57 ` [PATCH v2 06/28] locking/rwlocks: Add contention detection for rwlocks Ben Gardon
2021-02-09 20:39 ` Guenter Roeck
2021-02-09 21:46 ` Waiman Long
2021-02-09 22:25 ` Guenter Roeck
2021-02-10 0:27 ` Waiman Long
2021-02-10 0:41 ` Waiman Long
2021-02-10 6:04 ` Guenter Roeck
2021-02-10 14:57 ` Waiman Long
2021-02-10 3:32 ` Waiman Long
2021-02-10 15:15 ` Waiman Long
2021-02-02 18:57 ` [PATCH v2 07/28] sched: Add needbreak " Ben Gardon
2021-02-02 18:57 ` [PATCH v2 08/28] sched: Add cond_resched_rwlock Ben Gardon
2021-02-02 18:57 ` [PATCH v2 09/28] KVM: x86/mmu: Fix braces in kvm_recover_nx_lpages Ben Gardon
2021-02-02 18:57 ` [PATCH v2 10/28] KVM: x86/mmu: Fix TDP MMU zap collapsible SPTEs Ben Gardon
2021-02-03 9:43 ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 11/28] KVM: x86/mmu: Merge flush and non-flush tdp_mmu_iter_cond_resched Ben Gardon
2021-02-02 18:57 ` [PATCH v2 12/28] KVM: x86/mmu: Rename goal_gfn to next_last_level_gfn Ben Gardon
2021-02-02 18:57 ` [PATCH v2 13/28] KVM: x86/mmu: Ensure forward progress when yielding in TDP MMU iter Ben Gardon
2021-02-05 23:42 ` Sean Christopherson
2021-02-02 18:57 ` Ben Gardon [this message]
2021-02-02 18:57 ` [PATCH v2 15/28] KVM: x86/mmu: Skip no-op changes in TDP MMU functions Ben Gardon
2021-02-02 18:57 ` [PATCH v2 16/28] KVM: x86/mmu: Clear dirtied pages mask bit before early break Ben Gardon
2021-02-02 18:57 ` [PATCH v2 17/28] KVM: x86/mmu: Protect TDP MMU page table memory with RCU Ben Gardon
2021-02-02 18:57 ` [PATCH v2 18/28] KVM: x86/mmu: Use an rwlock for the x86 MMU Ben Gardon
2021-02-02 18:57 ` [PATCH v2 19/28] KVM: x86/mmu: Factor out functions to add/remove TDP MMU pages Ben Gardon
2021-02-02 18:57 ` [PATCH v2 20/28] KVM: x86/mmu: Use atomic ops to set SPTEs in TDP MMU map Ben Gardon
2021-02-03 2:48 ` kernel test robot
2021-02-03 11:14 ` Paolo Bonzini
2021-02-06 0:26 ` Sean Christopherson
2021-02-08 10:32 ` Paolo Bonzini
2021-04-01 10:32 ` Paolo Bonzini
2021-04-01 16:50 ` Ben Gardon
2021-04-01 17:32 ` Paolo Bonzini
2021-04-01 18:09 ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 21/28] KVM: x86/mmu: Flush TLBs after zap in TDP MMU PF handler Ben Gardon
2021-02-06 0:29 ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 22/28] KVM: x86/mmu: Mark SPTEs in disconnected pages as removed Ben Gardon
2021-02-03 11:17 ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 23/28] KVM: x86/mmu: Allow parallel page faults for the TDP MMU Ben Gardon
2021-02-03 12:39 ` Paolo Bonzini
2021-02-03 17:46 ` Ben Gardon
2021-02-03 18:30 ` Paolo Bonzini
2021-02-06 0:12 ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 24/28] KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock Ben Gardon
2021-02-03 11:25 ` Paolo Bonzini
2021-02-03 11:26 ` Paolo Bonzini
2021-02-03 18:31 ` Ben Gardon
2021-02-03 18:32 ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 25/28] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU " Ben Gardon
2021-02-03 11:34 ` Paolo Bonzini
2021-02-03 18:51 ` Ben Gardon
2021-02-02 18:57 ` [PATCH v2 26/28] KVM: x86/mmu: Allow enabling / disabling dirty logging under " Ben Gardon
2021-02-03 11:38 ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 27/28] KVM: selftests: Add backing src parameter to dirty_log_perf_test Ben Gardon
2021-02-02 18:57 ` [PATCH v2 28/28] KVM: selftests: Disable dirty logging with vCPUs running Ben Gardon
2021-02-03 10:07 ` Paolo Bonzini
2021-02-03 11:00 ` [PATCH v2 00/28] Allow parallel MMU operations with TDP MMU Paolo Bonzini
2021-02-03 17:54 ` Sean Christopherson
2021-02-03 18:13 ` Paolo Bonzini
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