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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5 8/9] ioreq-server: make buffered ioreq handling optional
Some emulators will only register regions that require non-buffered
access. (In practice the only region that a guest uses buffered access
for today is the VGA aperture from 0xa0000-0xbffff). This patch therefore
makes allocation of the buffered ioreq page and event channel optional for
secondary ioreq servers.
If a guest attempts buffered access to an ioreq server that does not
support it, the access will be handled via the normal synchronous path.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
---
tools/libxc/xc_domain.c | 2 ++
tools/libxc/xenctrl.h | 1 +
xen/arch/x86/hvm/hvm.c | 65 ++++++++++++++++++++++++++-------------
xen/include/public/hvm/hvm_op.h | 24 +++++++++------
4 files changed, 62 insertions(+), 30 deletions(-)
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 99101e7..67090bd 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -1286,6 +1286,7 @@ int xc_get_hvm_param(xc_interface *handle, domid_t dom,
int param, unsigned long
int xc_hvm_create_ioreq_server(xc_interface *xch,
domid_t domid,
+ int handle_bufioreq,
ioservid_t *id)
{
DECLARE_HYPERCALL;
@@ -1301,6 +1302,7 @@ int xc_hvm_create_ioreq_server(xc_interface *xch,
hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg);
arg->domid = domid;
+ arg->handle_bufioreq = !!handle_bufioreq;
rc = do_xen_hypercall(xch, &hypercall);
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 74aa2bf..60f6abc 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -1801,6 +1801,7 @@ int xc_get_hvm_param(xc_interface *handle, domid_t dom,
int param, unsigned long
*/
int xc_hvm_create_ioreq_server(xc_interface *xch,
domid_t domid,
+ int handle_bufioreq,
ioservid_t *id);
/**
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 5715ed4..e734adb 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -761,7 +761,7 @@ static int hvm_ioreq_server_add_vcpu(struct
hvm_ioreq_server *s,
sv->ioreq_evtchn = rc;
- if ( v->vcpu_id == 0 )
+ if ( v->vcpu_id == 0 && s->bufioreq.va != NULL )
{
struct domain *d = s->domain;
@@ -811,7 +811,7 @@ static void hvm_ioreq_server_remove_vcpu(struct
hvm_ioreq_server *s,
list_del_init(&sv->list_entry);
- if ( v->vcpu_id == 0 )
+ if ( v->vcpu_id == 0 && s->bufioreq.va != NULL )
free_xen_event_channel(v, s->bufioreq_evtchn);
free_xen_event_channel(v, sv->ioreq_evtchn);
@@ -838,7 +838,7 @@ static void hvm_ioreq_server_remove_all_vcpus(struct
hvm_ioreq_server *s)
list_del_init(&sv->list_entry);
- if ( v->vcpu_id == 0 )
+ if ( v->vcpu_id == 0 && s->bufioreq.va != NULL )
free_xen_event_channel(v, s->bufioreq_evtchn);
free_xen_event_channel(v, sv->ioreq_evtchn);
@@ -850,7 +850,7 @@ static void hvm_ioreq_server_remove_all_vcpus(struct
hvm_ioreq_server *s)
}
static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s,
- bool_t is_default)
+ bool_t is_default, bool_t
handle_bufioreq)
{
struct domain *d = s->domain;
unsigned long ioreq_pfn, bufioreq_pfn;
@@ -858,24 +858,34 @@ static int hvm_ioreq_server_map_pages(struct
hvm_ioreq_server *s,
if ( is_default ) {
ioreq_pfn = d->arch.hvm_domain.params[HVM_PARAM_IOREQ_PFN];
+
+ /*
+ * The default ioreq server must handle buffered ioreqs, for
+ * backwards compatibility.
+ */
+ ASSERT(handle_bufioreq);
bufioreq_pfn = d->arch.hvm_domain.params[HVM_PARAM_BUFIOREQ_PFN];
} else {
rc = hvm_alloc_ioreq_gmfn(d, &ioreq_pfn);
if ( rc )
goto fail1;
- rc = hvm_alloc_ioreq_gmfn(d, &bufioreq_pfn);
- if ( rc )
- goto fail2;
+ if ( handle_bufioreq ) {
+ rc = hvm_alloc_ioreq_gmfn(d, &bufioreq_pfn);
+ if ( rc )
+ goto fail2;
+ }
}
rc = hvm_map_ioreq_page(s, 0, ioreq_pfn);
if ( rc )
goto fail3;
- rc = hvm_map_ioreq_page(s, 1, bufioreq_pfn);
- if ( rc )
- goto fail4;
+ if ( handle_bufioreq ) {
+ rc = hvm_map_ioreq_page(s, 1, bufioreq_pfn);
+ if ( rc )
+ goto fail4;
+ }
return 0;
@@ -883,7 +893,7 @@ fail4:
hvm_unmap_ioreq_page(s, 0);
fail3:
- if ( !is_default )
+ if ( !is_default && handle_bufioreq )
hvm_free_ioreq_gmfn(d, bufioreq_pfn);
fail2:
@@ -898,12 +908,17 @@ static void hvm_ioreq_server_unmap_pages(struct
hvm_ioreq_server *s,
bool_t is_default)
{
struct domain *d = s->domain;
+ bool_t handle_bufioreq = ( s->bufioreq.va != NULL );
+
+ if ( handle_bufioreq )
+ hvm_unmap_ioreq_page(s, 1);
- hvm_unmap_ioreq_page(s, 1);
hvm_unmap_ioreq_page(s, 0);
if ( !is_default ) {
- hvm_free_ioreq_gmfn(d, s->bufioreq.gmfn);
+ if ( handle_bufioreq )
+ hvm_free_ioreq_gmfn(d, s->bufioreq.gmfn);
+
hvm_free_ioreq_gmfn(d, s->ioreq.gmfn);
}
}
@@ -982,7 +997,7 @@ static void hvm_ioreq_server_disable(struct
hvm_ioreq_server *s)
static int hvm_ioreq_server_init(struct hvm_ioreq_server *s, struct domain *d,
domid_t domid, bool_t is_default,
- ioservid_t id)
+ bool_t handle_bufioreq, ioservid_t id)
{
struct vcpu *v;
int rc;
@@ -1002,7 +1017,7 @@ static int hvm_ioreq_server_init(struct hvm_ioreq_server
*s, struct domain *d,
if ( rc )
goto fail1;
- rc = hvm_ioreq_server_map_pages(s, is_default);
+ rc = hvm_ioreq_server_map_pages(s, is_default, handle_bufioreq);
if ( rc )
goto fail2;
@@ -1043,7 +1058,8 @@ static void hvm_ioreq_server_deinit(struct
hvm_ioreq_server *s,
}
static int hvm_create_ioreq_server(struct domain *d, domid_t domid,
- bool_t is_default, ioservid_t *id)
+ bool_t is_default, bool_t handle_bufioreq,
+ ioservid_t *id)
{
struct hvm_ioreq_server *s;
int rc;
@@ -1060,7 +1076,7 @@ static int hvm_create_ioreq_server(struct domain *d,
domid_t domid,
if ( is_default && d->arch.hvm_domain.default_ioreq_server != NULL )
goto fail2;
- rc = hvm_ioreq_server_init(s, d, domid, is_default,
+ rc = hvm_ioreq_server_init(s, d, domid, is_default, handle_bufioreq,
d->arch.hvm_domain.ioreq_server_id++);
if ( rc )
goto fail3;
@@ -1146,8 +1162,11 @@ static int hvm_get_ioreq_server_info(struct domain *d,
ioservid_t id,
continue;
*ioreq_pfn = s->ioreq.gmfn;
- *bufioreq_pfn = s->bufioreq.gmfn;
- *bufioreq_port = s->bufioreq_evtchn;
+
+ if ( s->bufioreq.va != NULL ) {
+ *bufioreq_pfn = s->bufioreq.gmfn;
+ *bufioreq_port = s->bufioreq_evtchn;
+ }
rc = 0;
break;
@@ -2390,6 +2409,9 @@ int hvm_buffered_io_send(ioreq_t *p)
iorp = &s->bufioreq;
pg = iorp->va;
+ if ( !pg )
+ return 0;
+
/*
* Return 0 for the cases we can't deal with:
* - 'addr' is only a 20-bit field, so we cannot address beyond 1MB
@@ -5139,7 +5161,8 @@ static int hvmop_create_ioreq_server(
if ( !is_hvm_domain(d) )
goto out;
- rc = hvm_create_ioreq_server(d, curr_d->domain_id, 0, &op.id);
+ rc = hvm_create_ioreq_server(d, curr_d->domain_id, 0,
+ !!op.handle_bufioreq, &op.id);
if ( rc != 0 )
goto out;
@@ -5543,7 +5566,7 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
/* May need to create server */
domid = d->arch.hvm_domain.params[HVM_PARAM_DM_DOMAIN];
- rc = hvm_create_ioreq_server(d, domid, 1, NULL);
+ rc = hvm_create_ioreq_server(d, domid, 1, 1, NULL);
if ( rc != 0 && rc != -EEXIST )
goto param_fail;
/*FALLTHRU*/
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 5ca1cb2..ab4b583 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -259,12 +259,15 @@ DEFINE_XEN_GUEST_HANDLE(ioservid_t);
* HVMOP_create_ioreq_server: Instantiate a new IOREQ Server for a secondary
* emulator servicing domain <domid>.
*
- * The <id> handed back is unique for <domid>.
+ * The <id> handed back is unique for <domid>. If <handle_bufioreq> is zero
+ * the buffered ioreq ring will not be allocated and hence all emulation
+ * requestes to this server will be synchronous.
*/
#define HVMOP_create_ioreq_server 17
struct xen_hvm_create_ioreq_server {
- domid_t domid; /* IN - domain to be serviced */
- ioservid_t id; /* OUT - server id */
+ domid_t domid; /* IN - domain to be serviced */
+ uint8_t handle_bufioreq; /* IN - should server handle buffered ioreqs */
+ ioservid_t id; /* OUT - server id */
};
typedef struct xen_hvm_create_ioreq_server xen_hvm_create_ioreq_server_t;
DEFINE_XEN_GUEST_HANDLE(xen_hvm_create_ioreq_server_t);
@@ -274,12 +277,15 @@ DEFINE_XEN_GUEST_HANDLE(xen_hvm_create_ioreq_server_t);
* IOREQ Server <id>.
*
* The emulator needs to map the synchronous ioreq structures and buffered
- * ioreq ring that Xen uses to request emulation. These are hosted in domain
- * <domid>'s gmfns <ioreq_pfn> and <bufioreq_pfn> respectively. In addition the
- * emulator needs to bind to event channel <bufioreq_port> to listen for
- * buffered emulation requests. (The event channels used for synchronous
- * emulation requests are specified in the per-CPU ioreq structures in
- * <ioreq_pfn>).
+ * ioreq ring (if it exists) that Xen uses to request emulation. These are
+ * hosted in domain <domid>'s gmfns <ioreq_pfn> and <bufioreq_pfn>
+ * respectively. In addition, if the IOREQ Server is handling buffered
+ * emulation requests, the emulator needs to bind to event channel
+ * <bufioreq_port> to listen for them. (The event channels used for
+ * synchronous emulation requests are specified in the per-CPU ioreq
+ * structures in <ioreq_pfn>).
+ * If the IOREQ Server is not handling buffered emulation requests then the
+ * values handed back in <bufioreq_pfn> and <bufioreq_port> will both be 0.
*/
#define HVMOP_get_ioreq_server_info 18
struct xen_hvm_get_ioreq_server_info {
--
1.7.10.4
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