From: Peter Xu <peterx@redhat.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Christophe de Dinechin <dinechin@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Yan Zhao <yan.y.zhao@intel.com>,
Alex Williamson <alex.williamson@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Kevin Kevin <kevin.tian@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
peterx@redhat.com,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH v3 02/21] drm/i915/gvt: subsitute kvm_read/write_guest with vfio_iova_rw
Date: Thu, 9 Jan 2020 09:57:10 -0500 [thread overview]
Message-ID: <20200109145729.32898-3-peterx@redhat.com> (raw)
In-Reply-To: <20200109145729.32898-1-peterx@redhat.com>
From: Yan Zhao <yan.y.zhao@intel.com>
As a device model, it is better to read/write guest memory using vfio
interface, so that vfio is able to maintain dirty info of device IOVAs.
Compared to CPU side interfaces kvm_read/write_guest(), vfio_iova_rw()
has ~600 cycles more overhead on average.
-------------------------------------
| interface | avg cpu cycles |
|-----------------------------------|
| kvm_write_guest | 1546 |
| ----------------------------------|
| kvm_read_guest | 686 |
|-----------------------------------|
| vfio_iova_rw(w) | 2233 |
|-----------------------------------|
| vfio_iova_rw(r) | 1262 |
-------------------------------------
Comparison of benchmarks scores are as blow:
---------------------------------------------------------
| avg score | kvm_read/write_guest | vfio_iova_rw |
---------------------------------------------------------
| Glmark2 | 1132 | 1138.2 |
---------------------------------------------------------
| Lightsmark | 61.558 | 61.538 |
|--------------------------------------------------------
| OpenArena | 142.77 | 136.6 |
---------------------------------------------------------
| Heaven | 698 | 686.8 |
--------------------------------------------------------
No obvious performance downgrade found.
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
[peterx: pass in "write" to vfio_iova_rw(), suggested by Paolo]
Signed-off-by: Peter Xu <peterx@redhat.com>
---
drivers/gpu/drm/i915/gvt/kvmgt.c | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 3259a1fa69e1..5fb82f285b98 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1968,31 +1968,18 @@ static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa,
void *buf, unsigned long len, bool write)
{
struct kvmgt_guest_info *info;
- struct kvm *kvm;
- int idx, ret;
- bool kthread = current->mm == NULL;
+ int ret;
+ struct intel_vgpu *vgpu;
+ struct device *dev;
if (!handle_valid(handle))
return -ESRCH;
info = (struct kvmgt_guest_info *)handle;
- kvm = info->kvm;
-
- if (kthread) {
- if (!mmget_not_zero(kvm->mm))
- return -EFAULT;
- use_mm(kvm->mm);
- }
-
- idx = srcu_read_lock(&kvm->srcu);
- ret = write ? kvm_write_guest(kvm, gpa, buf, len) :
- kvm_read_guest(kvm, gpa, buf, len);
- srcu_read_unlock(&kvm->srcu, idx);
+ vgpu = info->vgpu;
+ dev = mdev_dev(vgpu->vdev.mdev);
- if (kthread) {
- unuse_mm(kvm->mm);
- mmput(kvm->mm);
- }
+ ret = vfio_iova_rw(dev, gpa, buf, len, write);
return ret;
}
--
2.24.1
next prev parent reply other threads:[~2020-01-09 14:57 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 14:57 [PATCH v3 00/21] KVM: Dirty ring interface Peter Xu
2020-01-09 14:57 ` [PATCH v3 01/21] vfio: introduce vfio_iova_rw to read/write a range of IOVAs Peter Xu
2020-01-09 14:57 ` Peter Xu [this message]
2020-01-09 14:57 ` [PATCH v3 03/21] KVM: Remove kvm_read_guest_atomic() Peter Xu
2020-01-09 14:57 ` [PATCH v3 04/21] KVM: Add build-time error check on kvm_run size Peter Xu
2020-01-09 14:57 ` [PATCH v3 05/21] KVM: X86: Change parameter for fast_page_fault tracepoint Peter Xu
2020-01-09 14:57 ` [PATCH v3 06/21] KVM: X86: Don't take srcu lock in init_rmode_identity_map() Peter Xu
2020-01-09 14:57 ` [PATCH v3 07/21] KVM: Cache as_id in kvm_memory_slot Peter Xu
2020-01-09 14:57 ` [PATCH v3 08/21] KVM: X86: Drop x86_set_memory_region() Peter Xu
2020-01-09 14:57 ` [PATCH v3 09/21] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR] Peter Xu
2020-01-19 9:01 ` Paolo Bonzini
2020-01-20 6:45 ` Peter Xu
2020-01-21 15:56 ` Sean Christopherson
2020-01-21 16:14 ` Paolo Bonzini
2020-01-28 5:50 ` Peter Xu
2020-01-28 18:24 ` Sean Christopherson
2020-01-31 15:08 ` Peter Xu
2020-01-31 19:33 ` Sean Christopherson
2020-01-31 20:28 ` Peter Xu
2020-01-31 20:36 ` Sean Christopherson
2020-01-31 20:55 ` Peter Xu
2020-01-31 21:29 ` Sean Christopherson
2020-01-31 22:16 ` Peter Xu
2020-01-31 22:20 ` Sean Christopherson
2020-01-09 14:57 ` [PATCH v3 10/21] KVM: Pass in kvm pointer into mark_page_dirty_in_slot() Peter Xu
2020-01-09 14:57 ` [PATCH v3 11/21] KVM: Move running VCPU from ARM to common code Peter Xu
2020-01-09 14:57 ` [PATCH v3 12/21] KVM: X86: Implement ring-based dirty memory tracking Peter Xu
2020-01-09 16:29 ` Michael S. Tsirkin
2020-01-09 16:56 ` Alex Williamson
2020-01-09 19:21 ` Peter Xu
2020-01-09 19:36 ` Michael S. Tsirkin
2020-01-09 19:15 ` Peter Xu
2020-01-09 19:35 ` Michael S. Tsirkin
2020-01-09 20:19 ` Peter Xu
2020-01-09 22:18 ` Michael S. Tsirkin
2020-01-10 15:29 ` Peter Xu
2020-01-12 6:24 ` Michael S. Tsirkin
2020-01-14 20:01 ` Peter Xu
2020-01-15 6:50 ` Michael S. Tsirkin
2020-01-15 15:20 ` Peter Xu
2020-01-19 9:09 ` Paolo Bonzini
2020-01-19 10:12 ` Michael S. Tsirkin
2020-01-20 7:29 ` Peter Xu
2020-01-20 7:47 ` Michael S. Tsirkin
2020-01-21 8:29 ` Peter Xu
2020-01-21 10:25 ` Paolo Bonzini
2020-01-21 10:24 ` Paolo Bonzini
2020-01-11 4:49 ` kbuild test robot
2020-01-11 23:19 ` kbuild test robot
2020-01-15 6:47 ` Michael S. Tsirkin
2020-01-15 15:27 ` Peter Xu
2020-01-16 8:38 ` Michael S. Tsirkin
2020-01-16 16:27 ` Peter Xu
2020-01-17 9:50 ` Michael S. Tsirkin
2020-01-20 6:48 ` Peter Xu
2020-01-09 14:57 ` [PATCH v3 13/21] KVM: Make dirty ring exclusive to dirty bitmap log Peter Xu
2020-01-09 14:57 ` [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled Peter Xu
2020-01-09 16:41 ` Peter Xu
2020-01-09 14:57 ` [PATCH v3 15/21] KVM: selftests: Always clear dirty bitmap after iteration Peter Xu
2020-01-09 14:57 ` [PATCH v3 16/21] KVM: selftests: Sync uapi/linux/kvm.h to tools/ Peter Xu
2020-01-09 14:57 ` [PATCH v3 17/21] KVM: selftests: Use a single binary for dirty/clear log test Peter Xu
2020-01-09 14:57 ` [PATCH v3 18/21] KVM: selftests: Introduce after_vcpu_run hook for dirty " Peter Xu
2020-01-09 14:57 ` [PATCH v3 19/21] KVM: selftests: Add dirty ring buffer test Peter Xu
2020-01-09 14:57 ` [PATCH v3 20/21] KVM: selftests: Let dirty_log_test async for dirty ring test Peter Xu
2020-01-09 14:57 ` [PATCH v3 21/21] KVM: selftests: Add "-c" parameter to dirty log test Peter Xu
2020-01-09 15:59 ` [PATCH v3 00/21] KVM: Dirty ring interface Michael S. Tsirkin
2020-01-09 16:17 ` Peter Xu
2020-01-09 16:40 ` Michael S. Tsirkin
2020-01-09 17:08 ` Peter Xu
2020-01-09 19:08 ` Michael S. Tsirkin
2020-01-09 19:39 ` Peter Xu
2020-01-09 20:42 ` Paolo Bonzini
2020-01-09 22:28 ` Michael S. Tsirkin
2020-01-10 15:10 ` Peter Xu
2020-01-09 16:47 ` Alex Williamson
2020-01-09 17:58 ` Peter Xu
2020-01-09 19:13 ` Michael S. Tsirkin
2020-01-09 19:23 ` Peter Xu
2020-01-09 19:37 ` Michael S. Tsirkin
2020-01-09 20:51 ` Paolo Bonzini
2020-01-09 22:21 ` Michael S. Tsirkin
2020-01-19 9:11 ` Paolo Bonzini
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