From: "Michael S. Tsirkin" <mst@redhat.com>
To: Gregory Haskins <ghaskins@novell.com>
Cc: linux-kernel@vger.kernel.org, agraf@suse.de,
pmullaney@novell.com, pmorreale@novell.com,
anthony@codemonkey.ws, rusty@rustcorp.com.au,
netdev@vger.kernel.org, kvm@vger.kernel.org, avi@redhat.com,
bhutchings@solarflare.com, andi@firstfloor.org, gregkh@suse.de,
herber@gondor.apana.org.au, chrisw@sous-sol.org,
shemminger@vyatta.com
Subject: Re: [RFC PATCH v2 03/19] vbus: add connection-client helper infrastructure
Date: Thu, 4 Jun 2009 21:06:11 +0300 [thread overview]
Message-ID: <20090604180611.GA16387@redhat.com> (raw)
In-Reply-To: <20090409163057.32740.27829.stgit@dev.haskins.net>
On Thu, Apr 09, 2009 at 12:30:57PM -0400, Gregory Haskins wrote:
> +static unsigned long
> +task_memctx_copy_to(struct vbus_memctx *ctx, void *dst, const void *src,
> + unsigned long n)
> +{
> + struct task_memctx *tm = to_task_memctx(ctx);
> + struct task_struct *p = tm->task;
> +
> + while (n) {
> + unsigned long offset = ((unsigned long)dst)%PAGE_SIZE;
> + unsigned long len = PAGE_SIZE - offset;
> + int ret;
> + struct page *pg;
> + void *maddr;
> +
> + if (len > n)
> + len = n;
> +
> + down_read(&p->mm->mmap_sem);
> + ret = get_user_pages(p, p->mm,
> + (unsigned long)dst, 1, 1, 0, &pg, NULL);
> +
> + if (ret != 1) {
> + up_read(&p->mm->mmap_sem);
> + break;
> + }
> +
> + maddr = kmap_atomic(pg, KM_USER0);
> + memcpy(maddr + offset, src, len);
> + kunmap_atomic(maddr, KM_USER0);
> + set_page_dirty_lock(pg);
> + put_page(pg);
> + up_read(&p->mm->mmap_sem);
> +
> + src += len;
> + dst += len;
> + n -= len;
> + }
> +
> + return n;
> +}
BTW, why did you decide to use get_user_pages?
Would switch_mm + copy_to_user work as well
avoiding page walk if all pages are present?
Also - if we just had vmexit because a process executed
io (or hypercall), can't we just do copy_to_user there?
Avi, I think at some point you said that we can?
--
MST
next prev parent reply other threads:[~2009-06-04 18:08 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-09 16:30 [RFC PATCH v2 00/19] virtual-bus Gregory Haskins
2009-04-09 16:30 ` [RFC PATCH v2 01/19] shm-signal: shared-memory signals Gregory Haskins
2009-04-09 16:30 ` [RFC PATCH v2 02/19] vbus: add virtual-bus definitions Gregory Haskins
2009-04-09 16:30 ` [RFC PATCH v2 03/19] vbus: add connection-client helper infrastructure Gregory Haskins
2009-06-04 18:06 ` Michael S. Tsirkin [this message]
2009-06-04 18:18 ` Gregory Haskins
2009-06-04 18:24 ` Avi Kivity
2009-06-04 18:30 ` Gregory Haskins
2009-06-04 19:04 ` Avi Kivity
2009-06-04 18:23 ` Avi Kivity
2009-04-09 16:31 ` [RFC PATCH v2 04/19] vbus: add bus-registration notifiers Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 05/19] vbus: add a "vbus-proxy" bus model for vbus_driver objects Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 06/19] ioq: Add basic definitions for a shared-memory, lockless queue Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 07/19] ioq: add vbus helpers Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 08/19] venet: add the ABI definitions for an 802.x packet interface Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 09/19] net: Add vbus_enet driver Gregory Haskins
2009-04-09 16:37 ` Stephen Hemminger
2009-04-09 19:50 ` Greg KH
2009-04-09 16:31 ` [RFC PATCH v2 10/19] venet-tap: Adds a "venet" compatible "tap" device to VBUS Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 11/19] venet: add scatter-gather support Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 12/19] venettap: " Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 13/19] x86: allow the irq->vector translation to be determined outside of ioapic Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 14/19] kvm: add a reset capability Gregory Haskins
2009-04-11 16:56 ` Avi Kivity
2009-04-09 16:32 ` [RFC PATCH v2 15/19] kvm: add dynamic IRQ support Gregory Haskins
2009-04-11 17:01 ` Avi Kivity
2009-04-13 17:44 ` Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 16/19] kvm: Add VBUS support to the host Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 17/19] kvm: Add guest-side support for VBUS Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 18/19] vbus: add a userspace connector Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 19/19] virtio: add a vbus transport Gregory Haskins
2009-08-09 16:40 ` Anthony Liguori
2009-08-10 15:40 ` Gregory Haskins
2009-04-09 16:48 ` [RFC PATCH v2 00/19] virtual-bus Gregory Haskins
2009-04-11 16:45 ` Avi Kivity
2009-06-04 18:49 ` Gregory Haskins
2009-06-05 4:55 ` Rusty Russell
2009-06-05 5:30 ` Paul E. McKenney
2009-06-05 14:55 ` Rusty Russell
2009-06-05 16:25 ` Paul E. McKenney
2009-06-11 13:21 ` Rusty Russell
2009-06-11 15:48 ` Paul E. McKenney
2009-06-05 11:56 ` Gregory Haskins
2009-06-05 12:53 ` Avi Kivity
2009-06-05 12:54 ` Gregory Haskins
2009-06-05 14:35 ` Rusty Russell
2009-06-05 14:44 ` Gregory Haskins
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