From: Chao Peng <chao.p.peng@linux.intel.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
qemu-devel@nongnu.org
Cc: 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>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
Chao Peng <chao.p.peng@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
Subject: [PATCH v4 08/12] KVM: Use memfile_pfn_ops to obtain pfn for private pages
Date: Tue, 18 Jan 2022 21:21:17 +0800 [thread overview]
Message-ID: <20220118132121.31388-9-chao.p.peng@linux.intel.com> (raw)
In-Reply-To: <20220118132121.31388-1-chao.p.peng@linux.intel.com>
Private pages are not mmap-ed into userspace so can not reply on
get_user_pages() to obtain the pfn. Instead we add a memfile_pfn_ops
pointer pfn_ops in each private memslot and use it to obtain the pfn
for a gfn. To do that, KVM should convert the gfn to the offset into
the fd and then call get_lock_pfn callback. Once KVM completes its job
it should call put_unlock_pfn to unlock the pfn. Note the pfn(page) is
locked between get_lock_pfn/put_unlock_pfn to ensure pfn is valid when
KVM uses it to establish the mapping in the secondary MMU page table.
The pfn_ops is initialized via memfile_register_notifier from the memory
backing store that provided the private_fd.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
arch/x86/kvm/Kconfig | 1 +
include/linux/kvm_host.h | 33 +++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index ebc8ce9ec917..5d5bebaad9e7 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -47,6 +47,7 @@ config KVM
select SRCU
select INTERVAL_TREE
select HAVE_KVM_PM_NOTIFIER if PM
+ select MEMFILE_NOTIFIER
help
Support hosting fully virtualized guest machines using hardware
virtualization extensions. You will need a fairly recent
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 26118a45f0bb..927e7f44a02a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -42,6 +42,7 @@
#include <asm/kvm_host.h>
#include <linux/kvm_dirty_ring.h>
+#include <linux/memfile_notifier.h>
#ifndef KVM_MAX_VCPU_IDS
#define KVM_MAX_VCPU_IDS KVM_MAX_VCPUS
@@ -460,6 +461,7 @@ struct kvm_memory_slot {
u16 as_id;
struct file *private_file;
loff_t private_offset;
+ struct memfile_pfn_ops *pfn_ops;
};
static inline bool kvm_slot_is_private(const struct kvm_memory_slot *slot)
@@ -810,6 +812,7 @@ static inline void kvm_irqfd_exit(void)
{
}
#endif
+
int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
struct module *module);
void kvm_exit(void);
@@ -2103,4 +2106,34 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
/* Max number of entries allowed for each kvm dirty ring */
#define KVM_DIRTY_RING_MAX_ENTRIES 65536
+#ifdef CONFIG_MEMFILE_NOTIFIER
+static inline long kvm_memfile_get_pfn(struct kvm_memory_slot *slot, gfn_t gfn,
+ int *order)
+{
+ pgoff_t index = gfn - slot->base_gfn +
+ (slot->private_offset >> PAGE_SHIFT);
+
+ return slot->pfn_ops->get_lock_pfn(file_inode(slot->private_file),
+ index, order);
+}
+
+static inline void kvm_memfile_put_pfn(struct kvm_memory_slot *slot,
+ kvm_pfn_t pfn)
+{
+ slot->pfn_ops->put_unlock_pfn(pfn);
+}
+
+#else
+static inline long kvm_memfile_get_pfn(struct kvm_memory_slot *slot, gfn_t gfn,
+ int *order)
+{
+ return -1;
+}
+
+static inline void kvm_memfile_put_pfn(struct kvm_memory_slot *slot,
+ kvm_pfn_t pfn)
+{
+}
+#endif /* CONFIG_MEMFILE_NOTIFIER */
+
#endif
--
2.17.1
next prev parent reply other threads:[~2022-01-18 13:23 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 13:21 [PATCH v4 00/12] KVM: mm: fd-based approach for supporting KVM guest private memory Chao Peng
2022-01-18 13:21 ` [PATCH v4 01/12] mm/shmem: Introduce F_SEAL_INACCESSIBLE Chao Peng
2022-02-07 12:24 ` Vlastimil Babka
2022-02-17 12:56 ` Chao Peng
2022-02-11 23:33 ` Andy Lutomirski
2022-02-17 13:06 ` Chao Peng
2022-02-17 19:09 ` Andy Lutomirski
2022-02-23 11:49 ` Chao Peng
2022-02-23 12:05 ` Steven Price
2022-03-04 19:24 ` Andy Lutomirski
2022-03-07 13:26 ` Chao Peng
2022-03-08 12:17 ` Paolo Bonzini
2022-01-18 13:21 ` [PATCH v4 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag Chao Peng
2022-01-21 15:50 ` Steven Price
2022-01-24 13:29 ` Chao Peng
2022-02-07 18:51 ` Vlastimil Babka
2022-02-08 8:49 ` David Hildenbrand
2022-02-08 18:22 ` Mike Rapoport
2022-01-18 13:21 ` [PATCH v4 03/12] mm: Introduce memfile_notifier Chao Peng
2022-03-07 15:42 ` Vlastimil Babka
2022-03-08 1:45 ` Chao Peng
2022-01-18 13:21 ` [PATCH v4 04/12] mm/shmem: Support memfile_notifier Chao Peng
2022-02-08 18:29 ` Mike Rapoport
2022-02-17 13:10 ` Chao Peng
2022-02-11 23:40 ` Andy Lutomirski
2022-02-17 13:23 ` Chao Peng
2022-01-18 13:21 ` [PATCH v4 05/12] KVM: Extend the memslot to support fd-based private memory Chao Peng
2022-01-18 13:21 ` [PATCH v4 06/12] KVM: Use kvm_userspace_memory_region_ext Chao Peng
2022-01-18 13:21 ` [PATCH v4 07/12] KVM: Add KVM_EXIT_MEMORY_ERROR exit Chao Peng
2022-01-18 13:21 ` Chao Peng [this message]
2022-01-18 13:21 ` [PATCH v4 09/12] KVM: Handle page fault for private memory Chao Peng
2022-01-18 13:21 ` [PATCH v4 10/12] KVM: Register private memslot to memory backing store Chao Peng
2022-01-18 13:21 ` [PATCH v4 11/12] KVM: Zap existing KVM mappings when pages changed in the private fd Chao Peng
2022-01-18 13:21 ` [PATCH v4 12/12] KVM: Expose KVM_MEM_PRIVATE Chao Peng
2022-01-25 20:20 ` Maciej S. Szmigiero
2022-02-17 13:45 ` Chao Peng
2022-02-22 1:16 ` Maciej S. Szmigiero
2022-02-23 12:00 ` Chao Peng
2022-02-23 18:32 ` Maciej S. Szmigiero
2022-02-24 8:07 ` Chao Peng
2022-01-28 16:47 ` [PATCH v4 00/12] KVM: mm: fd-based approach for supporting KVM guest private memory Steven Price
2022-02-02 2:28 ` Nakajima, Jun
2022-02-02 9:23 ` Steven Price
2022-02-02 20:47 ` Nakajima, Jun
2022-02-08 18:33 ` Mike Rapoport
2022-02-17 13:47 ` Chao Peng
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220118132121.31388-9-chao.p.peng@linux.intel.com \
--to=chao.p.peng@linux.intel.com \
--cc=ak@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=bfields@fieldses.org \
--cc=bp@alien8.de \
--cc=corbet@lwn.net \
--cc=dave.hansen@intel.com \
--cc=david@redhat.com \
--cc=hpa@zytor.com \
--cc=hughd@google.com \
--cc=jlayton@kernel.org \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=jun.nakajima@intel.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=x86@kernel.org \
--cc=yu.c.zhang@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).