From: Isaku Yamahata <isaku.yamahata@gmail.com>
To: Chao Peng <chao.p.peng@linux.intel.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-api@vger.kernel.org, linux-doc@vger.kernel.org,
qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Hugh Dickins <hughd@google.com>, Jeff Layton <jlayton@kernel.org>,
"J . Bruce Fields" <bfields@fieldses.org>,
Andrew Morton <akpm@linux-foundation.org>,
Shuah Khan <shuah@kernel.org>, Mike Rapoport <rppt@kernel.org>,
Steven Price <steven.price@arm.com>,
"Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
Vlastimil Babka <vbabka@suse.cz>,
Vishal Annapurve <vannapurve@google.com>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com,
ak@linux.intel.com, david@redhat.com, aarcange@redhat.com,
ddutile@redhat.com, dhildenb@redhat.com,
Quentin Perret <qperret@google.com>,
Michael Roth <michael.roth@amd.com>,
mhocko@suse.com, Muchun Song <songmuchun@bytedance.com>,
wei.w.wang@intel.com, isaku.yamahata@gmail.com
Subject: Re: [PATCH v8 6/8] KVM: Update lpage info when private/shared memory are mixed
Date: Thu, 29 Sep 2022 09:52:06 -0700 [thread overview]
Message-ID: <20220929165206.GA1963093@ls.amr.corp.intel.com> (raw)
In-Reply-To: <20220915142913.2213336-7-chao.p.peng@linux.intel.com>
On Thu, Sep 15, 2022 at 10:29:11PM +0800,
Chao Peng <chao.p.peng@linux.intel.com> wrote:
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 08abad4f3e6f..a0f198cede3d 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
...
> @@ -6894,3 +6899,115 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
> if (kvm->arch.nx_lpage_recovery_thread)
> kthread_stop(kvm->arch.nx_lpage_recovery_thread);
> }
> +
> +static bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr,
> + gfn_t start, gfn_t end)
> +{
> + XA_STATE(xas, &kvm->mem_attr_array, start);
> + gfn_t gfn = start;
> + void *entry;
> + bool shared, private;
> + bool mixed = false;
> +
> + if (attr == KVM_MEM_ATTR_SHARED) {
> + shared = true;
> + private = false;
> + } else {
> + shared = false;
> + private = true;
> + }
We don't have to care the target is shared or private. We need to check
only same or not.
> +
> + rcu_read_lock();
> + entry = xas_load(&xas);
> + while (gfn < end) {
> + if (xas_retry(&xas, entry))
> + continue;
> +
> + KVM_BUG_ON(gfn != xas.xa_index, kvm);
> +
> + if (entry)
> + private = true;
> + else
> + shared = true;
> +
> + if (private && shared) {
> + mixed = true;
> + goto out;
> + }
> +
> + entry = xas_next(&xas);
> + gfn++;
> + }
> +out:
> + rcu_read_unlock();
> + return mixed;
> +}
> +
> +static inline void update_mixed(struct kvm_lpage_info *linfo, bool mixed)
> +{
> + if (mixed)
> + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED;
> + else
> + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED;
> +}
> +
> +static void update_mem_lpage_info(struct kvm *kvm,
> + struct kvm_memory_slot *slot,
> + unsigned int attr,
> + gfn_t start, gfn_t end)
> +{
> + unsigned long lpage_start, lpage_end;
> + unsigned long gfn, pages, mask;
> + int level;
> +
> + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) {
> + pages = KVM_PAGES_PER_HPAGE(level);
> + mask = ~(pages - 1);
> + lpage_start = start & mask;
> + lpage_end = (end - 1) & mask;
> +
> + /*
> + * We only need to scan the head and tail page, for middle pages
> + * we know they are not mixed.
> + */
> + update_mixed(lpage_info_slot(lpage_start, slot, level),
> + mem_attr_is_mixed(kvm, attr, lpage_start,
> + lpage_start + pages));
> +
> + if (lpage_start == lpage_end)
> + return;
> +
> + for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages)
> + update_mixed(lpage_info_slot(gfn, slot, level), false);
For >2M case, we don't have to check all entry. just check lower level case.
> +
> + update_mixed(lpage_info_slot(lpage_end, slot, level),
> + mem_attr_is_mixed(kvm, attr, lpage_end,
> + lpage_end + pages));
> + }
> +}
> +
> +void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr,
> + gfn_t start, gfn_t end)
> +{
> + struct kvm_memory_slot *slot;
> + struct kvm_memslots *slots;
> + struct kvm_memslot_iter iter;
> + int i;
> +
> + WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)),
> + "Unsupported mem attribute.\n");
> +
> + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
> + slots = __kvm_memslots(kvm, i);
> +
> + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) {
> + slot = iter.slot;
> + start = max(start, slot->base_gfn);
> + end = min(end, slot->base_gfn + slot->npages);
> + if (WARN_ON_ONCE(start >= end))
> + continue;
> +
> + update_mem_lpage_info(kvm, slot, attr, start, end);
> + }
> + }
> +}
Here is my updated version.
bool kvm_mem_attr_is_mixed(struct kvm_memory_slot *slot, gfn_t gfn, int level)
{
gfn_t pages = KVM_PAGES_PER_HPAGE(level);
gfn_t mask = ~(pages - 1);
struct kvm_lpage_info *linfo = lpage_info_slot(gfn & mask, slot, level);
WARN_ON_ONCE(level == PG_LEVEL_4K);
return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED;
}
#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM_ATTR
static void update_mixed(struct kvm_lpage_info *linfo, bool mixed)
{
if (mixed)
linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED;
else
linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED;
}
static bool __mem_attr_is_mixed(struct kvm *kvm, gfn_t start, gfn_t end)
{
XA_STATE(xas, &kvm->mem_attr_array, start);
bool mixed = false;
gfn_t gfn = start;
void *s_entry;
void *entry;
rcu_read_lock();
s_entry = xas_load(&xas);
entry = s_entry;
while (gfn < end) {
if (xas_retry(&xas, entry))
continue;
KVM_BUG_ON(gfn != xas.xa_index, kvm);
entry = xas_next(&xas);
if (entry != s_entry) {
mixed = true;
break;
}
gfn++;
}
rcu_read_unlock();
return mixed;
}
static bool mem_attr_is_mixed(struct kvm *kvm,
struct kvm_memory_slot *slot, int level,
gfn_t start, gfn_t end)
{
struct kvm_lpage_info *child_linfo;
unsigned long child_pages;
bool mixed = false;
unsigned long gfn;
void *entry;
if (WARN_ON_ONCE(level == PG_LEVEL_4K))
return false;
if (level == PG_LEVEL_2M)
return __mem_attr_is_mixed(kvm, start, end);
/* This assumes that level - 1 is already updated. */
rcu_read_lock();
child_pages = KVM_PAGES_PER_HPAGE(level - 1);
entry = xa_load(&kvm->mem_attr_array, start);
for (gfn = start; gfn < end; gfn += child_pages) {
child_linfo = lpage_info_slot(gfn, slot, level - 1);
if (child_linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED) {
mixed = true;
break;
}
if (xa_load(&kvm->mem_attr_array, gfn) != entry) {
mixed = true;
break;
}
}
rcu_read_unlock();
return mixed;
}
static void update_mem_lpage_info(struct kvm *kvm,
struct kvm_memory_slot *slot,
unsigned int attr,
gfn_t start, gfn_t end)
{
unsigned long lpage_start, lpage_end;
unsigned long gfn, pages, mask;
int level;
for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) {
pages = KVM_PAGES_PER_HPAGE(level);
mask = ~(pages - 1);
lpage_start = start & mask;
lpage_end = (end - 1) & mask;
/*
* We only need to scan the head and tail page, for middle pages
* we know they are not mixed.
*/
update_mixed(lpage_info_slot(lpage_start, slot, level),
mem_attr_is_mixed(kvm, slot, level,
lpage_start, lpage_start + pages));
if (lpage_start == lpage_end)
return;
for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages)
update_mixed(lpage_info_slot(gfn, slot, level), false);
update_mixed(lpage_info_slot(lpage_end, slot, level),
mem_attr_is_mixed(kvm, slot, level,
lpage_end, lpage_end + pages));
}
}
void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr,
gfn_t start, gfn_t end)
{
struct kvm_memory_slot *slot;
struct kvm_memslots *slots;
struct kvm_memslot_iter iter;
int idx;
int i;
WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)),
"Unsupported mem attribute.\n");
idx = srcu_read_lock(&kvm->srcu);
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
slots = __kvm_memslots(kvm, i);
kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) {
slot = iter.slot;
start = max(start, slot->base_gfn);
end = min(end, slot->base_gfn + slot->npages);
if (WARN_ON_ONCE(start >= end))
continue;
update_mem_lpage_info(kvm, slot, attr, start, end);
}
}
srcu_read_unlock(&kvm->srcu, idx);
}
#endif
--
Isaku Yamahata <isaku.yamahata@gmail.com>
next prev parent reply other threads:[~2022-09-29 16:52 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-15 14:29 [PATCH v8 0/8] KVM: mm: fd-based approach for supporting KVM Chao Peng
2022-09-15 14:29 ` [PATCH v8 1/8] mm/memfd: Introduce userspace inaccessible memfd Chao Peng
2022-09-19 9:12 ` David Hildenbrand
2022-09-19 19:10 ` Sean Christopherson
2022-09-21 21:10 ` Andy Lutomirski
2022-09-22 13:23 ` Wang, Wei W
2022-09-23 15:20 ` Fuad Tabba
2022-09-23 15:19 ` Fuad Tabba
2022-09-26 14:23 ` Chao Peng
2022-09-26 15:51 ` Fuad Tabba
2022-09-27 22:47 ` Sean Christopherson
2022-09-30 16:19 ` Fuad Tabba
2022-10-13 13:34 ` Chao Peng
2022-10-17 10:31 ` Fuad Tabba
2022-10-17 14:58 ` Chao Peng
2022-10-17 19:05 ` Fuad Tabba
2022-10-19 13:30 ` Chao Peng
2022-10-18 0:33 ` Sean Christopherson
2022-10-19 15:04 ` Fuad Tabba
2022-09-23 0:58 ` Kirill A . Shutemov
2022-09-26 10:35 ` David Hildenbrand
2022-09-26 14:48 ` Kirill A. Shutemov
2022-09-26 14:53 ` David Hildenbrand
2022-09-27 23:23 ` Sean Christopherson
2022-09-28 13:36 ` Kirill A. Shutemov
2022-09-22 13:26 ` Wang, Wei W
2022-09-22 19:49 ` Sean Christopherson
2022-09-23 0:53 ` Kirill A . Shutemov
2022-09-23 15:20 ` Fuad Tabba
2022-09-30 16:14 ` Fuad Tabba
2022-09-30 16:23 ` Kirill A . Shutemov
2022-10-03 7:33 ` Fuad Tabba
2022-10-03 11:01 ` Kirill A. Shutemov
2022-10-04 15:39 ` Fuad Tabba
2022-10-06 8:50 ` Fuad Tabba
2022-10-06 13:04 ` Kirill A. Shutemov
2022-10-17 13:00 ` Vlastimil Babka
2022-10-17 16:19 ` Kirill A . Shutemov
2022-10-17 16:39 ` Gupta, Pankaj
2022-10-17 21:56 ` Kirill A . Shutemov
2022-10-18 13:42 ` Vishal Annapurve
2022-10-19 15:32 ` Kirill A . Shutemov
2022-10-20 10:50 ` Vishal Annapurve
2022-10-21 13:54 ` Chao Peng
2022-10-21 16:53 ` Sean Christopherson
2022-10-19 12:23 ` Vishal Annapurve
2022-10-21 13:47 ` Chao Peng
2022-10-21 16:18 ` Sean Christopherson
2022-10-24 14:59 ` Kirill A . Shutemov
2022-10-24 15:26 ` David Hildenbrand
2022-11-03 16:27 ` Vishal Annapurve
2022-09-15 14:29 ` [PATCH v8 2/8] KVM: Extend the memslot to support fd-based private memory Chao Peng
2022-09-16 9:14 ` Bagas Sanjaya
2022-09-16 9:53 ` Chao Peng
2022-09-26 10:26 ` Fuad Tabba
2022-09-26 14:04 ` Chao Peng
2022-09-29 22:45 ` Isaku Yamahata
2022-09-29 23:22 ` Sean Christopherson
2022-10-05 13:04 ` Jarkko Sakkinen
2022-10-05 22:05 ` Jarkko Sakkinen
2022-10-06 9:00 ` Fuad Tabba
2022-10-06 14:58 ` Jarkko Sakkinen
2022-10-06 15:07 ` Jarkko Sakkinen
2022-10-06 15:34 ` Sean Christopherson
2022-10-07 11:14 ` Jarkko Sakkinen
2022-10-07 14:58 ` Sean Christopherson
2022-10-07 21:54 ` Jarkko Sakkinen
2022-10-08 16:15 ` Jarkko Sakkinen
2022-10-08 17:35 ` Jarkko Sakkinen
2022-10-10 8:25 ` Chao Peng
2022-10-12 8:14 ` Jarkko Sakkinen
2022-09-15 14:29 ` [PATCH v8 3/8] KVM: Add KVM_EXIT_MEMORY_FAULT exit Chao Peng
2022-09-16 9:17 ` Bagas Sanjaya
2022-09-16 9:54 ` Chao Peng
2022-09-15 14:29 ` [PATCH v8 4/8] KVM: Use gfn instead of hva for mmu_notifier_retry Chao Peng
2022-09-15 14:29 ` [PATCH v8 5/8] KVM: Register/unregister the guest private memory regions Chao Peng
2022-09-26 10:36 ` Fuad Tabba
2022-09-26 14:07 ` Chao Peng
2022-10-11 9:48 ` Fuad Tabba
2022-10-12 2:35 ` Chao Peng
2022-10-17 10:15 ` Fuad Tabba
2022-10-17 22:17 ` Sean Christopherson
2022-10-19 13:23 ` Chao Peng
2022-10-19 15:02 ` Fuad Tabba
2022-10-19 16:09 ` Sean Christopherson
2022-10-19 18:32 ` Fuad Tabba
2022-09-15 14:29 ` [PATCH v8 6/8] KVM: Update lpage info when private/shared memory are mixed Chao Peng
2022-09-29 16:52 ` Isaku Yamahata [this message]
2022-09-30 8:59 ` Chao Peng
2022-09-15 14:29 ` [PATCH v8 7/8] KVM: Handle page fault for private memory Chao Peng
2022-10-14 18:57 ` Sean Christopherson
2022-10-17 14:48 ` Chao Peng
2022-09-15 14:29 ` [PATCH v8 8/8] KVM: Enable and expose KVM_MEM_PRIVATE Chao Peng
2022-10-04 14:55 ` Jarkko Sakkinen
2022-10-10 8:31 ` Chao Peng
2022-10-06 8:55 ` Fuad Tabba
2022-10-10 8:33 ` Chao Peng
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