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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v5 2/5] xen/common/domctl: introduce XEN_DOMCTL_get/setdomaincontext
These domctls provide a mechanism to get and set domain context from
the toolstack.
Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien@xxxxxxx>
---
Cc: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <george.dunlap@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
v4:
- Add missing zero pad checks
v3:
- Addressed comments from Julien and Jan
- Use vmalloc() rather than xmalloc_bytes()
v2:
- drop mask parameter
- const-ify some more buffers
---
tools/flask/policy/modules/xen.if | 4 +-
tools/libxc/include/xenctrl.h | 5 +
tools/libxc/xc_domain.c | 56 +++++++++
xen/common/domctl.c | 173 ++++++++++++++++++++++++++++
xen/include/public/domctl.h | 41 +++++++
xen/xsm/flask/hooks.c | 6 +
xen/xsm/flask/policy/access_vectors | 4 +
7 files changed, 287 insertions(+), 2 deletions(-)
diff --git a/tools/flask/policy/modules/xen.if
b/tools/flask/policy/modules/xen.if
index 8eb2293a52..2bc9db4f64 100644
--- a/tools/flask/policy/modules/xen.if
+++ b/tools/flask/policy/modules/xen.if
@@ -53,7 +53,7 @@ define(`create_domain_common', `
allow $1 $2:domain2 { set_cpu_policy settsc setscheduler setclaim
set_vnumainfo get_vnumainfo cacheflush
psr_cmt_op psr_alloc soft_reset
- resource_map get_cpu_policy };
+ resource_map get_cpu_policy setcontext };
allow $1 $2:security check_context;
allow $1 $2:shadow enable;
allow $1 $2:mmu { map_read map_write adjust memorymap physmap pinpage
mmuext_op updatemp };
@@ -97,7 +97,7 @@ define(`migrate_domain_out', `
allow $1 $2:hvm { gethvmc getparam };
allow $1 $2:mmu { stat pageinfo map_read };
allow $1 $2:domain { getaddrsize getvcpucontext pause destroy };
- allow $1 $2:domain2 gettsc;
+ allow $1 $2:domain2 { gettsc getcontext };
allow $1 $2:shadow { enable disable logdirty };
')
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 45ff7db1e8..0ce2372e2f 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -867,6 +867,11 @@ int xc_domain_hvm_setcontext(xc_interface *xch,
uint8_t *hvm_ctxt,
uint32_t size);
+int xc_domain_getcontext(xc_interface *xch, uint32_t domid,
+ void *ctxt_buf, size_t *size);
+int xc_domain_setcontext(xc_interface *xch, uint32_t domid,
+ const void *ctxt_buf, size_t size);
+
/**
* This function will return guest IO ABI protocol
*
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 71829c2bce..e462a6f728 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -537,6 +537,62 @@ int xc_domain_hvm_setcontext(xc_interface *xch,
return ret;
}
+int xc_domain_getcontext(xc_interface *xch, uint32_t domid,
+ void *ctxt_buf, size_t *size)
+{
+ int ret;
+ DECLARE_DOMCTL = {
+ .cmd = XEN_DOMCTL_getdomaincontext,
+ .domain = domid,
+ .u.getdomaincontext.size = *size,
+ };
+ DECLARE_HYPERCALL_BOUNCE(ctxt_buf, *size, XC_HYPERCALL_BUFFER_BOUNCE_OUT);
+
+ if ( xc_hypercall_bounce_pre(xch, ctxt_buf) )
+ return -1;
+
+ set_xen_guest_handle(domctl.u.setdomaincontext.buffer, ctxt_buf);
+
+ ret = do_domctl(xch, &domctl);
+
+ xc_hypercall_bounce_post(xch, ctxt_buf);
+
+ if ( ret )
+ return ret;
+
+ *size = domctl.u.getdomaincontext.size;
+ if ( *size != domctl.u.getdomaincontext.size )
+ {
+ errno = EOVERFLOW;
+ return -1;
+ }
+
+ return 0;
+}
+
+int xc_domain_setcontext(xc_interface *xch, uint32_t domid,
+ const void *ctxt_buf, size_t size)
+{
+ int ret;
+ DECLARE_DOMCTL = {
+ .cmd = XEN_DOMCTL_setdomaincontext,
+ .domain = domid,
+ .u.setdomaincontext.size = size,
+ };
+ DECLARE_HYPERCALL_BOUNCE_IN(ctxt_buf, size);
+
+ if ( xc_hypercall_bounce_pre(xch, ctxt_buf) )
+ return -1;
+
+ set_xen_guest_handle(domctl.u.setdomaincontext.buffer, ctxt_buf);
+
+ ret = do_domctl(xch, &domctl);
+
+ xc_hypercall_bounce_post(xch, ctxt_buf);
+
+ return ret;
+}
+
int xc_vcpu_getcontext(xc_interface *xch,
uint32_t domid,
uint32_t vcpu,
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index a69b3b59a8..44758034a6 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -25,6 +25,8 @@
#include <xen/hypercall.h>
#include <xen/vm_event.h>
#include <xen/monitor.h>
+#include <xen/save.h>
+#include <xen/vmap.h>
#include <asm/current.h>
#include <asm/irq.h>
#include <asm/page.h>
@@ -358,6 +360,168 @@ static struct vnuma_info *vnuma_init(const struct
xen_domctl_vnuma *uinfo,
return ERR_PTR(ret);
}
+struct domctl_context
+{
+ void *buffer;
+ struct domain_save_descriptor *desc;
+ size_t len;
+ size_t cur;
+};
+
+static int dry_run_append(void *priv, const void *data, size_t len)
+{
+ struct domctl_context *c = priv;
+
+ if ( c->len + len < c->len )
+ return -EOVERFLOW;
+
+ c->len += len;
+
+ return 0;
+}
+
+static int dry_run_begin(void *priv, const struct domain_save_descriptor *desc)
+{
+ return dry_run_append(priv, NULL, sizeof(*desc));
+}
+
+static int dry_run_end(void *priv, size_t len)
+{
+ return 0;
+}
+
+static struct domain_save_ops dry_run_ops = {
+ .begin = dry_run_begin,
+ .append = dry_run_append,
+ .end = dry_run_end,
+};
+
+static int save_begin(void *priv, const struct domain_save_descriptor *desc)
+{
+ struct domctl_context *c = priv;
+
+ if ( c->len - c->cur < sizeof(*desc) )
+ return -ENOSPC;
+
+ c->desc = c->buffer + c->cur; /* stash pointer to descriptor */
+ *c->desc = *desc;
+
+ c->cur += sizeof(*desc);
+
+ return 0;
+}
+
+static int save_append(void *priv, const void *data, size_t len)
+{
+ struct domctl_context *c = priv;
+
+ if ( c->len - c->cur < len )
+ return -ENOSPC;
+
+ memcpy(c->buffer + c->cur, data, len);
+ c->cur += len;
+
+ return 0;
+}
+
+static int save_end(void *priv, size_t len)
+{
+ struct domctl_context *c = priv;
+
+ c->desc->length = len;
+
+ return 0;
+}
+
+static struct domain_save_ops save_ops = {
+ .begin = save_begin,
+ .append = save_append,
+ .end = save_end,
+};
+
+static int getdomaincontext(struct domain *d,
+ struct xen_domctl_getdomaincontext *gdc)
+{
+ struct domctl_context c = { .buffer = ZERO_BLOCK_PTR };
+ int rc;
+
+ if ( d == current->domain )
+ return -EPERM;
+
+ if ( gdc->pad )
+ return -EINVAL;
+
+ if ( guest_handle_is_null(gdc->buffer) ) /* query for buffer size */
+ {
+ if ( gdc->size )
+ return -EINVAL;
+
+ /* dry run to acquire buffer size */
+ rc = domain_save(d, &dry_run_ops, &c, true);
+ if ( rc )
+ return rc;
+
+ gdc->size = c.len;
+ return 0;
+ }
+
+ c.len = gdc->size;
+ c.buffer = vmalloc(c.len);
+ if ( !c.buffer )
+ return -ENOMEM;
+
+ rc = domain_save(d, &save_ops, &c, false);
+
+ gdc->size = c.cur;
+ if ( !rc && copy_to_guest(gdc->buffer, c.buffer, gdc->size) )
+ rc = -EFAULT;
+
+ vfree(c.buffer);
+
+ return rc;
+}
+
+static int load_read(void *priv, void *data, size_t len)
+{
+ struct domctl_context *c = priv;
+
+ if ( c->len - c->cur < len )
+ return -ENODATA;
+
+ memcpy(data, c->buffer + c->cur, len);
+ c->cur += len;
+
+ return 0;
+}
+
+static struct domain_load_ops load_ops = {
+ .read = load_read,
+};
+
+static int setdomaincontext(struct domain *d,
+ const struct xen_domctl_setdomaincontext *sdc)
+{
+ struct domctl_context c = { .buffer = ZERO_BLOCK_PTR, .len = sdc->size };
+ int rc;
+
+ if ( d == current->domain )
+ return -EPERM;
+
+ if ( sdc->pad )
+ return -EINVAL;
+
+ c.buffer = vmalloc(c.len);
+ if ( !c.buffer )
+ return -ENOMEM;
+
+ rc = !copy_from_guest(c.buffer, sdc->buffer, c.len) ?
+ domain_load(d, &load_ops, &c) : -EFAULT;
+
+ vfree(c.buffer);
+
+ return rc;
+}
+
long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
{
long ret = 0;
@@ -942,6 +1106,15 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t)
u_domctl)
copyback = 1;
break;
+ case XEN_DOMCTL_getdomaincontext:
+ ret = getdomaincontext(d, &op->u.getdomaincontext);
+ copyback = !ret;
+ break;
+
+ case XEN_DOMCTL_setdomaincontext:
+ ret = setdomaincontext(d, &op->u.setdomaincontext);
+ break;
+
default:
ret = arch_do_domctl(op, d, u_domctl);
break;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 1ad34c35eb..1b133bda59 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1129,6 +1129,43 @@ struct xen_domctl_vuart_op {
*/
};
+/*
+ * XEN_DOMCTL_getdomaincontext
+ * ---------------------------
+ *
+ * buffer (IN): The buffer into which the context data should be
+ * copied, or NULL to query the buffer size that should
+ * be allocated.
+ * size (IN/OUT): If 'buffer' is NULL then the value passed in must be
+ * zero, and the value passed out will be the size of the
+ * buffer to allocate.
+ * If 'buffer' is non-NULL then the value passed in must
+ * be the size of the buffer into which data may be copied.
+ * The value passed out will be the size of data written.
+ */
+struct xen_domctl_getdomaincontext {
+ uint32_t size;
+ uint32_t pad;
+ XEN_GUEST_HANDLE_64(void) buffer;
+};
+
+/* XEN_DOMCTL_setdomaincontext
+ * ---------------------------
+ *
+ * buffer (IN): The buffer from which the context data should be
+ * copied.
+ * size (IN): The size of the buffer from which data may be copied.
+ * This data must include DOMAIN_SAVE_CODE_HEADER at the
+ * start and terminate with a DOMAIN_SAVE_CODE_END record.
+ * Any data beyond the DOMAIN_SAVE_CODE_END record will be
+ * ignored.
+ */
+struct xen_domctl_setdomaincontext {
+ uint32_t size;
+ uint32_t pad;
+ XEN_GUEST_HANDLE_64(const_void) buffer;
+};
+
struct xen_domctl {
uint32_t cmd;
#define XEN_DOMCTL_createdomain 1
@@ -1210,6 +1247,8 @@ struct xen_domctl {
#define XEN_DOMCTL_vuart_op 81
#define XEN_DOMCTL_get_cpu_policy 82
#define XEN_DOMCTL_set_cpu_policy 83
+#define XEN_DOMCTL_getdomaincontext 84
+#define XEN_DOMCTL_setdomaincontext 85
#define XEN_DOMCTL_gdbsx_guestmemio 1000
#define XEN_DOMCTL_gdbsx_pausevcpu 1001
#define XEN_DOMCTL_gdbsx_unpausevcpu 1002
@@ -1270,6 +1309,8 @@ struct xen_domctl {
struct xen_domctl_monitor_op monitor_op;
struct xen_domctl_psr_alloc psr_alloc;
struct xen_domctl_vuart_op vuart_op;
+ struct xen_domctl_getdomaincontext getdomaincontext;
+ struct xen_domctl_setdomaincontext setdomaincontext;
uint8_t pad[128];
} u;
};
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 4649e6fd95..6f3db276ef 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -745,6 +745,12 @@ static int flask_domctl(struct domain *d, int cmd)
case XEN_DOMCTL_get_cpu_policy:
return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__GET_CPU_POLICY);
+ case XEN_DOMCTL_setdomaincontext:
+ return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__SETCONTEXT);
+
+ case XEN_DOMCTL_getdomaincontext:
+ return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__GETCONTEXT);
+
default:
return avc_unknown_permission("domctl", cmd);
}
diff --git a/xen/xsm/flask/policy/access_vectors
b/xen/xsm/flask/policy/access_vectors
index c055c14c26..fccfb9de82 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -245,6 +245,10 @@ class domain2
resource_map
# XEN_DOMCTL_get_cpu_policy
get_cpu_policy
+# XEN_DOMCTL_setdomaincontext
+ setcontext
+# XEN_DOMCTL_getdomaincontext
+ getcontext
}
# Similar to class domain, but primarily contains domctls related to HVM
domains
--
2.20.1
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