From: Joao Martins <joao.m.martins@oracle.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
xen-devel@lists.xenproject.org
Cc: "Ankur Arora" <ankur.a.arora@oracle.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Joao Martins" <joao.m.martins@oracle.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH RFC 38/39] xen-blkback: xen_shim_domain() support
Date: Wed, 20 Feb 2019 20:16:08 +0000 [thread overview]
Message-ID: <20190220201609.28290-39-joao.m.martins@oracle.com> (raw)
In-Reply-To: <20190220201609.28290-1-joao.m.martins@oracle.com>
With xen_shim_domain() enabled, the struct pages used for grant mappings
are only valid in the interval between GNTTABOP_map_grant_ref and
GNTTABOP_unmap_grant_ref.
Ensure that we do not cache the struct page outside that duration.
Also, update the struct page for the segment after
GNTTABOP_map_grant_ref, for the subsequent tracking or when doing IO.
In addition, we disable persistent grants for this configuration, since
the map/unmap overhead is fairly small (in the fast path, page lookup,
get_page() and put_page().) This reduces the memory usage in
blkback/blkfront.
Co-developed-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
drivers/block/xen-blkback/blkback.c | 19 ++++++++++++++++---
drivers/block/xen-blkback/xenbus.c | 5 +++--
2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index d51d88be88e1..20c15e6787b1 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -167,6 +167,15 @@ static inline void put_free_pages(struct xen_blkif_ring *ring, struct page **pag
unsigned long flags;
int i;
+ /*
+ * We don't own the struct page after unmap has been called.
+ * Reallocation is cheap anyway for the shim domain case, so free it.
+ */
+ if (xen_shim_domain()) {
+ gnttab_free_pages(num, page);
+ return;
+ }
+
spin_lock_irqsave(&ring->free_pages_lock, flags);
for (i = 0; i < num; i++)
list_add(&page[i]->lru, &ring->free_pages);
@@ -825,7 +834,7 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
*/
again:
for (i = map_until; i < num; i++) {
- uint32_t flags;
+ uint32_t flags = 0;
if (use_persistent_gnts) {
persistent_gnt = get_persistent_gnt(
@@ -846,7 +855,8 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
addr = vaddr(pages[i]->page);
pages_to_gnt[segs_to_map] = pages[i]->page;
pages[i]->persistent_gnt = NULL;
- flags = GNTMAP_host_map;
+ if (!xen_shim_domain())
+ flags = GNTMAP_host_map;
if (!use_persistent_gnts && ro)
flags |= GNTMAP_readonly;
gnttab_set_map_op(&map[segs_to_map++], addr,
@@ -880,6 +890,8 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
goto next;
}
pages[seg_idx]->handle = map[new_map_idx].handle;
+ if (xen_shim_domain())
+ pages[seg_idx]->page = pages_to_gnt[new_map_idx];
} else {
continue;
}
@@ -1478,7 +1490,7 @@ static int __init xen_blkif_init(void)
{
int rc = 0;
- if (!xen_domain())
+ if (!xen_domain() && !xen_shim_domain_get())
return -ENODEV;
if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
@@ -1508,6 +1520,7 @@ static void __exit xen_blkif_exit(void)
{
xen_blkif_interface_exit();
xen_blkif_xenbus_exit();
+ xen_shim_domain_put();
}
module_exit(xen_blkif_exit);
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 424e2efebe85..11be0c052b77 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -871,7 +871,8 @@ static void connect(struct backend_info *be)
xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
- err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+ err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u",
+ !xen_shim_domain());
if (err) {
xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
dev->nodename);
@@ -1059,7 +1060,7 @@ static int connect_ring(struct backend_info *be)
}
pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
0);
- be->blkif->vbd.feature_gnt_persistent = pers_grants;
+ be->blkif->vbd.feature_gnt_persistent = pers_grants && !xen_shim_domain();
be->blkif->vbd.overflow_max_grants = 0;
/*
--
2.11.0
next prev parent reply other threads:[~2019-02-20 20:19 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 20:15 [PATCH RFC 00/39] x86/KVM: Xen HVM guest support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 01/39] KVM: x86: fix Xen hypercall page msr handling Joao Martins
2019-02-22 1:30 ` Sean Christopherson
2019-02-22 11:47 ` Joao Martins
2019-02-22 12:51 ` Paolo Bonzini
2020-11-30 10:39 ` David Woodhouse
2020-11-30 11:03 ` Paolo Bonzini
2020-11-30 11:27 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 02/39] KVM: x86/xen: intercept xen hypercalls if enabled Joao Martins
2019-02-21 18:29 ` Sean Christopherson
2019-02-21 20:56 ` Joao Martins
2019-02-22 0:30 ` Sean Christopherson
2019-02-22 12:50 ` Paolo Bonzini
2020-12-01 9:48 ` David Woodhouse
2020-12-01 11:19 ` David Woodhouse
2020-12-02 11:17 ` Joao Martins
2020-12-02 12:12 ` David Woodhouse
2020-12-02 5:19 ` Ankur Arora
2020-12-02 8:03 ` David Woodhouse
2020-12-02 18:20 ` Ankur Arora
2019-02-20 20:15 ` [PATCH RFC 03/39] KVM: x86/xen: register shared_info page Joao Martins
2020-12-01 13:07 ` David Woodhouse
2020-12-02 0:40 ` Ankur Arora
2020-12-02 1:26 ` David Woodhouse
2020-12-02 5:17 ` Ankur Arora
2020-12-02 10:50 ` Joao Martins
2020-12-02 10:44 ` Joao Martins
2020-12-02 12:20 ` David Woodhouse
2020-12-02 20:32 ` Ankur Arora
2020-12-03 10:16 ` David Woodhouse
2020-12-04 17:30 ` Sean Christopherson
2020-12-02 20:33 ` Ankur Arora
2020-12-12 12:07 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 04/39] KVM: x86/xen: setup pvclock updates Joao Martins
2019-02-20 20:15 ` [PATCH RFC 05/39] KVM: x86/xen: update wallclock region Joao Martins
2019-02-20 20:15 ` [PATCH RFC 06/39] KVM: x86/xen: register vcpu info Joao Martins
2019-02-20 20:15 ` [PATCH RFC 07/39] KVM: x86/xen: register vcpu time info region Joao Martins
2019-02-20 20:15 ` [PATCH RFC 08/39] KVM: x86/xen: register steal clock Joao Martins
2019-02-20 20:15 ` [PATCH RFC 09/39] KVM: x86: declare Xen HVM guest capability Joao Martins
2019-02-20 20:15 ` [PATCH RFC 10/39] KVM: x86/xen: support upcall vector Joao Martins
2020-12-02 11:17 ` David Woodhouse
2020-12-02 13:12 ` Joao Martins
2020-12-02 16:47 ` David Woodhouse
2020-12-02 18:34 ` Joao Martins
2020-12-02 19:02 ` David Woodhouse
2020-12-02 20:12 ` Joao Martins
2020-12-02 20:37 ` David Woodhouse
2020-12-03 1:08 ` Ankur Arora
2020-12-08 16:08 ` David Woodhouse
2020-12-09 6:35 ` Ankur Arora
2020-12-09 10:27 ` David Woodhouse
2020-12-09 10:51 ` Joao Martins
2020-12-09 11:39 ` David Woodhouse
2020-12-09 13:26 ` Joao Martins
2020-12-09 15:41 ` David Woodhouse
2020-12-09 16:12 ` Joao Martins
2021-01-01 14:33 ` David Woodhouse
2021-01-05 12:11 ` Joao Martins
2021-01-05 13:23 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 11/39] KVM: x86/xen: evtchn signaling via eventfd Joao Martins
2020-11-30 9:41 ` David Woodhouse
2020-11-30 12:17 ` Joao Martins
2020-11-30 12:55 ` David Woodhouse
2020-11-30 15:08 ` Joao Martins
2020-11-30 16:48 ` David Woodhouse
2020-11-30 17:15 ` Joao Martins
2020-11-30 18:01 ` David Woodhouse
2020-11-30 18:41 ` Joao Martins
2020-11-30 19:04 ` David Woodhouse
2020-11-30 19:25 ` Joao Martins
2021-11-23 13:15 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 12/39] KVM: x86/xen: store virq when assigning evtchn Joao Martins
[not found] ` <b750291466f3c89e0a393e48079c087704b217a5.camel@amazon.co.uk>
2022-02-10 12:17 ` Joao Martins
2022-02-10 15:23 ` [EXTERNAL] " David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 13/39] KVM: x86/xen: handle PV timers oneshot mode Joao Martins
2019-02-20 20:15 ` [PATCH RFC 14/39] KVM: x86/xen: handle PV IPI vcpu yield Joao Martins
2019-02-20 20:15 ` [PATCH RFC 15/39] KVM: x86/xen: handle PV spinlocks slowpath Joao Martins
2022-02-08 12:36 ` David Woodhouse
2022-02-10 12:17 ` Joao Martins
2022-02-10 14:11 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 16/39] KVM: x86: declare Xen HVM evtchn offload capability Joao Martins
2019-02-20 20:15 ` [PATCH RFC 17/39] x86/xen: export vcpu_info and shared_info Joao Martins
2019-02-20 20:15 ` [PATCH RFC 18/39] x86/xen: make hypercall_page generic Joao Martins
2019-02-20 20:15 ` [PATCH RFC 19/39] xen/xenbus: xenbus uninit support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 20/39] xen-blkback: module_exit support Joao Martins
2019-02-25 18:57 ` Konrad Rzeszutek Wilk
2019-02-26 11:20 ` Joao Martins
2019-02-20 20:15 ` [PATCH RFC 21/39] KVM: x86/xen: domid allocation Joao Martins
2019-02-20 20:15 ` [PATCH RFC 22/39] KVM: x86/xen: grant table init Joao Martins
2019-02-20 20:15 ` [PATCH RFC 23/39] KVM: x86/xen: grant table grow support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 24/39] KVM: x86/xen: backend hypercall support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 25/39] KVM: x86/xen: grant map support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 26/39] KVM: x86/xen: grant unmap support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 27/39] KVM: x86/xen: grant copy support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 28/39] KVM: x86/xen: interdomain evtchn support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 29/39] KVM: x86/xen: evtchn unmask support Joao Martins
2019-02-20 20:16 ` [PATCH RFC 30/39] KVM: x86/xen: add additional evtchn ops Joao Martins
2019-02-20 20:16 ` [PATCH RFC 31/39] xen-shim: introduce shim domain driver Joao Martins
2019-02-20 20:16 ` [PATCH RFC 32/39] xen/balloon: xen_shim_domain() support Joao Martins
2019-02-20 20:16 ` [PATCH RFC 33/39] xen/grant-table: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 34/39] xen/gntdev: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 35/39] xen/xenbus: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 36/39] drivers/xen: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 37/39] xen-netback: " Joao Martins
2019-02-20 20:16 ` Joao Martins [this message]
2019-02-20 20:16 ` [PATCH RFC 39/39] KVM: x86: declare Xen HVM Dom0 capability Joao Martins
2019-02-20 21:09 ` [PATCH RFC 00/39] x86/KVM: Xen HVM guest support Paolo Bonzini
2019-02-21 0:29 ` Ankur Arora
2019-02-21 11:45 ` Joao Martins
2019-02-22 16:59 ` Paolo Bonzini
2019-03-12 17:14 ` Joao Martins
2019-04-08 6:44 ` Juergen Gross
2019-04-08 10:36 ` Joao Martins
2019-04-08 10:42 ` Juergen Gross
2019-04-08 17:31 ` Joao Martins
2019-04-09 0:35 ` Stefano Stabellini
2019-04-10 5:50 ` [Xen-devel] " Ankur Arora
2019-04-10 20:45 ` Stefano Stabellini
2019-04-09 5:04 ` Juergen Gross
2019-04-10 6:55 ` Ankur Arora
2019-04-10 7:14 ` Juergen Gross
2019-02-20 23:39 ` [Xen-devel] " Marek Marczykowski-Górecki
2019-02-21 0:31 ` Ankur Arora
2019-02-21 7:57 ` Juergen Gross
2019-02-21 12:00 ` Joao Martins
2019-02-21 11:55 ` Joao Martins
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