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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 01/18] xen: reinstate previously unused XENMEM_remove_from_physmap hypercall
From: Alex Zeffertt <alex.zeffertt@xxxxxxxxxxxxx>
This patch reinstates the XENMEM_remove_from_physmap hypercall
which was removed in 19041:ee62aaafff46 because it was not used.
However, is now needed in order to support xenstored stub domains.
The xenstored stub domain is not priviliged like dom0 and so cannot
unilaterally map the xenbus page of other guests into it's address
space. Therefore, before creating a domU the domain builder needs to
seed its grant table with a grant ref allowing the xenstored stub
domain to access the new domU's xenbus page.
At present domU's do not start with their grant table mapped.
Instead it gets mapped when the guest requests a grant table from
the hypervisor.
In order to seed the grant table, the domain builder first needs to
map it into dom0 address space. But the hypercall to do this
requires a gpfn (guest pfn), which is an mfn for PV guest, but a pfn
for HVM guests. Therfore, in order to seed the grant table of an
HVM guest, dom0 needs to *temporarily* map it into the guest's
"physical" address space.
Hence the need to reinstate the XENMEM_remove_from_physmap hypercall.
Signed-off-by: Alex Zeffertt <alex.zeffertt@xxxxxxxxxxxxx>
Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
xen/arch/ia64/xen/mm.c | 34 ++++++++++++++++++++++++++++++++++
xen/arch/x86/mm.c | 35 +++++++++++++++++++++++++++++++++++
xen/arch/x86/x86_64/compat/mm.c | 14 ++++++++++++++
xen/include/public/memory.h | 16 ++++++++++++++++
xen/include/xlat.lst | 1 +
xen/include/xsm/xsm.h | 6 ++++++
xen/xsm/dummy.c | 6 ++++++
xen/xsm/flask/hooks.c | 6 ++++++
8 files changed, 118 insertions(+), 0 deletions(-)
diff --git a/xen/arch/ia64/xen/mm.c b/xen/arch/ia64/xen/mm.c
index 694bf95..1b42e25 100644
--- a/xen/arch/ia64/xen/mm.c
+++ b/xen/arch/ia64/xen/mm.c
@@ -3447,6 +3447,40 @@ arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
break;
}
+ case XENMEM_remove_from_physmap:
+ {
+ struct xen_remove_from_physmap xrfp;
+ unsigned long mfn;
+ struct domain *d;
+
+ if ( copy_from_guest(&xrfp, arg, 1) )
+ return -EFAULT;
+
+ rc = rcu_lock_target_domain_by_id(xrfp.domid, &d);
+ if ( rc != 0 )
+ return rc;
+
+ if ( xsm_remove_from_physmap(current->domain, d) )
+ {
+ rcu_unlock_domain(d);
+ return -EPERM;
+ }
+
+ domain_lock(d);
+
+ mfn = gmfn_to_mfn(d, xrfp.gpfn);
+
+ if ( mfn_valid(mfn) )
+ guest_physmap_remove_page(d, xrfp.gpfn, mfn, 0);
+
+ domain_unlock(d);
+
+ rcu_unlock_domain(d);
+
+ break;
+ }
+
+
case XENMEM_machine_memory_map:
{
struct xen_memory_map memmap;
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 52222dd..0b5332b 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4871,6 +4871,41 @@ long arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
return rc;
}
+ case XENMEM_remove_from_physmap:
+ {
+ struct xen_remove_from_physmap xrfp;
+ unsigned long mfn;
+ struct domain *d;
+
+ if ( copy_from_guest(&xrfp, arg, 1) )
+ return -EFAULT;
+
+ rc = rcu_lock_target_domain_by_id(xrfp.domid, &d);
+ if ( rc != 0 )
+ return rc;
+
+ if ( xsm_remove_from_physmap(current->domain, d) )
+ {
+ rcu_unlock_domain(d);
+ return -EPERM;
+ }
+
+ domain_lock(d);
+
+ mfn = get_gfn_untyped(d, xrfp.gpfn);
+
+ if ( mfn_valid(mfn) )
+ guest_physmap_remove_page(d, xrfp.gpfn, mfn, PAGE_ORDER_4K);
+
+ put_gfn(d, xrfp.gpfn);
+
+ domain_unlock(d);
+
+ rcu_unlock_domain(d);
+
+ break;
+ }
+
case XENMEM_set_memory_map:
{
struct xen_foreign_memory_map fmap;
diff --git a/xen/arch/x86/x86_64/compat/mm.c b/xen/arch/x86/x86_64/compat/mm.c
index bea94fe..dde5430 100644
--- a/xen/arch/x86/x86_64/compat/mm.c
+++ b/xen/arch/x86/x86_64/compat/mm.c
@@ -82,6 +82,20 @@ int compat_arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
break;
}
+ case XENMEM_remove_from_physmap:
+ {
+ struct compat_remove_from_physmap cmp;
+ struct xen_remove_from_physmap *nat = (void
*)COMPAT_ARG_XLAT_VIRT_BASE;
+
+ if ( copy_from_guest(&cmp, arg, 1) )
+ return -EFAULT;
+
+ XLAT_remove_from_physmap(nat, &cmp);
+ rc = arch_memory_op(op, guest_handle_from_ptr(nat, void));
+
+ break;
+ }
+
case XENMEM_set_memory_map:
{
struct compat_foreign_memory_map cmp;
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index c5b78a8..308deff 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -229,6 +229,22 @@ struct xen_add_to_physmap {
typedef struct xen_add_to_physmap xen_add_to_physmap_t;
DEFINE_XEN_GUEST_HANDLE(xen_add_to_physmap_t);
+/*
+ * Unmaps the page appearing at a particular GPFN from the specified guest's
+ * pseudophysical address space.
+ * arg == addr of xen_remove_from_physmap_t.
+ */
+#define XENMEM_remove_from_physmap 15
+struct xen_remove_from_physmap {
+ /* Which domain to change the mapping for. */
+ domid_t domid;
+
+ /* GPFN of the current mapping of the page. */
+ xen_pfn_t gpfn;
+};
+typedef struct xen_remove_from_physmap xen_remove_from_physmap_t;
+DEFINE_XEN_GUEST_HANDLE(xen_remove_from_physmap_t);
+
/*** REMOVED ***/
/*#define XENMEM_translate_gpfn_list 8*/
diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
index 3d92175..9e67259 100644
--- a/xen/include/xlat.lst
+++ b/xen/include/xlat.lst
@@ -54,6 +54,7 @@
! kexec_image kexec.h
! kexec_range kexec.h
! add_to_physmap memory.h
+! remove_from_physmap memory.h
! foreign_memory_map memory.h
! memory_exchange memory.h
! memory_map memory.h
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index df6cec2..566c808 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -169,6 +169,7 @@ struct xsm_operations {
int (*update_va_mapping) (struct domain *d, struct domain *f,
l1_pgentry_t pte);
int (*add_to_physmap) (struct domain *d1, struct domain *d2);
+ int (*remove_from_physmap) (struct domain *d1, struct domain *d2);
int (*sendtrigger) (struct domain *d);
int (*bind_pt_irq) (struct domain *d, struct xen_domctl_bind_pt_irq *bind);
int (*unbind_pt_irq) (struct domain *d);
@@ -738,6 +739,11 @@ static inline int xsm_add_to_physmap(struct domain *d1,
struct domain *d2)
return xsm_call(add_to_physmap(d1, d2));
}
+static inline int xsm_remove_from_physmap(struct domain *d1, struct domain *d2)
+{
+ return xsm_call(remove_from_physmap(d1, d2));
+}
+
static inline int xsm_sendtrigger(struct domain *d)
{
return xsm_call(sendtrigger(d));
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index 4bbfbff..65daa4e 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -529,6 +529,11 @@ static int dummy_add_to_physmap (struct domain *d1, struct
domain *d2)
return 0;
}
+static int dummy_remove_from_physmap (struct domain *d1, struct domain *d2)
+{
+ return 0;
+}
+
static int dummy_sendtrigger (struct domain *d)
{
return 0;
@@ -690,6 +695,7 @@ void xsm_fixup_ops (struct xsm_operations *ops)
set_to_dummy_if_null(ops, mmu_machphys_update);
set_to_dummy_if_null(ops, update_va_mapping);
set_to_dummy_if_null(ops, add_to_physmap);
+ set_to_dummy_if_null(ops, remove_from_physmap);
set_to_dummy_if_null(ops, sendtrigger);
set_to_dummy_if_null(ops, bind_pt_irq);
set_to_dummy_if_null(ops, pin_mem_cacheattr);
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 0d35767..a2020a9 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1283,6 +1283,11 @@ static int flask_add_to_physmap(struct domain *d1,
struct domain *d2)
return domain_has_perm(d1, d2, SECCLASS_MMU, MMU__PHYSMAP);
}
+static int flask_remove_from_physmap(struct domain *d1, struct domain *d2)
+{
+ return domain_has_perm(d1, d2, SECCLASS_MMU, MMU__PHYSMAP);
+}
+
static int flask_sendtrigger(struct domain *d)
{
return domain_has_perm(current->domain, d, SECCLASS_DOMAIN,
DOMAIN__TRIGGER);
@@ -1550,6 +1555,7 @@ static struct xsm_operations flask_ops = {
.mmu_machphys_update = flask_mmu_machphys_update,
.update_va_mapping = flask_update_va_mapping,
.add_to_physmap = flask_add_to_physmap,
+ .remove_from_physmap = flask_remove_from_physmap,
.sendtrigger = flask_sendtrigger,
.get_device_group = flask_get_device_group,
.test_assign_device = flask_test_assign_device,
--
1.7.7.5
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