From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/virt/kvm/async_pf.c | 93 ++++++++++++++++++----------------------------
1 files changed, 37 insertions(+), 56 deletions(-)
diff --git a/kernel/virt/kvm/async_pf.c b/kernel/virt/kvm/async_pf.c
index c9861c2..dd77768 100644
--- a/kernel/virt/kvm/async_pf.c
+++ b/kernel/virt/kvm/async_pf.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* kvm asynchronous fault support
*
@@ -5,19 +6,6 @@
*
* Author:
* Gleb Natapov <gleb@redhat.com>
- *
- * This file is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/kvm_host.h>
@@ -28,21 +16,6 @@
#include "async_pf.h"
#include <trace/events/kvm.h>
-
-static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu,
- struct kvm_async_pf *work)
-{
-#ifdef CONFIG_KVM_ASYNC_PF_SYNC
- kvm_arch_async_page_present(vcpu, work);
-#endif
-}
-static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu,
- struct kvm_async_pf *work)
-{
-#ifndef CONFIG_KVM_ASYNC_PF_SYNC
- kvm_arch_async_page_present(vcpu, work);
-#endif
-}
static struct kmem_cache *async_pf_cache;
@@ -78,26 +51,32 @@
unsigned long addr = apf->addr;
gpa_t cr2_or_gpa = apf->cr2_or_gpa;
int locked = 1;
+ bool first;
might_sleep();
/*
- * This work is run asynchromously to the task which owns
+ * This work is run asynchronously to the task which owns
* mm and might be done in another context, so we must
* access remotely.
*/
- down_read(&mm->mmap_sem);
- get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL,
+ mmap_read_lock(mm);
+ get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, NULL,
&locked);
if (locked)
- up_read(&mm->mmap_sem);
+ mmap_read_unlock(mm);
- kvm_async_page_present_sync(vcpu, apf);
+ if (IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC))
+ kvm_arch_async_page_present(vcpu, apf);
spin_lock(&vcpu->async_pf.lock);
+ first = list_empty(&vcpu->async_pf.done);
list_add_tail(&apf->link, &vcpu->async_pf.done);
apf->vcpu = NULL;
spin_unlock(&vcpu->async_pf.lock);
+
+ if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC) && first)
+ kvm_arch_async_page_present_queued(vcpu);
/*
* apf may be freed by kvm_check_async_pf_completion() after
@@ -106,8 +85,7 @@
trace_kvm_async_pf_completed(addr, cr2_or_gpa);
- if (swq_has_sleeper(&vcpu->wq))
- swake_up_one(&vcpu->wq);
+ rcuwait_wake_up(&vcpu->wait);
mmput(mm);
kvm_put_kvm(vcpu->kvm);
@@ -161,7 +139,7 @@
struct kvm_async_pf *work;
while (!list_empty_careful(&vcpu->async_pf.done) &&
- kvm_arch_can_inject_async_page_present(vcpu)) {
+ kvm_arch_can_dequeue_async_page_present(vcpu)) {
spin_lock(&vcpu->async_pf.lock);
work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
link);
@@ -169,7 +147,8 @@
spin_unlock(&vcpu->async_pf.lock);
kvm_arch_async_page_ready(vcpu, work);
- kvm_async_page_present_async(vcpu, work);
+ if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC))
+ kvm_arch_async_page_present(vcpu, work);
list_del(&work->queue);
vcpu->async_pf.queued--;
@@ -177,15 +156,21 @@
}
}
-int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
- unsigned long hva, struct kvm_arch_async_pf *arch)
+/*
+ * Try to schedule a job to handle page fault asynchronously. Returns 'true' on
+ * success, 'false' on failure (page fault has to be handled synchronously).
+ */
+bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+ unsigned long hva, struct kvm_arch_async_pf *arch)
{
struct kvm_async_pf *work;
if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
- return 0;
+ return false;
- /* setup delayed work */
+ /* Arch specific code should not do async PF in this case */
+ if (unlikely(kvm_is_error_hva(hva)))
+ return false;
/*
* do alloc nowait since if we are going to sleep anyway we
@@ -193,7 +178,7 @@
*/
work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT | __GFP_NOWARN);
if (!work)
- return 0;
+ return false;
work->wakeup_all = false;
work->vcpu = vcpu;
@@ -204,29 +189,21 @@
mmget(work->mm);
kvm_get_kvm(work->vcpu->kvm);
- /* this can't really happen otherwise gfn_to_pfn_async
- would succeed */
- if (unlikely(kvm_is_error_hva(work->addr)))
- goto retry_sync;
-
INIT_WORK(&work->work, async_pf_execute);
- if (!schedule_work(&work->work))
- goto retry_sync;
list_add_tail(&work->queue, &vcpu->async_pf.queue);
vcpu->async_pf.queued++;
- kvm_arch_async_page_not_present(vcpu, work);
- return 1;
-retry_sync:
- kvm_put_kvm(work->vcpu->kvm);
- mmput(work->mm);
- kmem_cache_free(async_pf_cache, work);
- return 0;
+ work->notpresent_injected = kvm_arch_async_page_not_present(vcpu, work);
+
+ schedule_work(&work->work);
+
+ return true;
}
int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
{
struct kvm_async_pf *work;
+ bool first;
if (!list_empty_careful(&vcpu->async_pf.done))
return 0;
@@ -239,9 +216,13 @@
INIT_LIST_HEAD(&work->queue); /* for list_del to work */
spin_lock(&vcpu->async_pf.lock);
+ first = list_empty(&vcpu->async_pf.done);
list_add_tail(&work->link, &vcpu->async_pf.done);
spin_unlock(&vcpu->async_pf.lock);
+ if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC) && first)
+ kvm_arch_async_page_present_queued(vcpu);
+
vcpu->async_pf.queued++;
return 0;
}
--
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