|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 1/2] x86/mem_sharing: make fork_reset more configurable
Allow specify distinct parts of the fork VM to be reset. This is useful when a
fuzzing operation involves mapping in only a handful of pages that are known
ahead of time. Throwing these pages away just to be re-copied immediately is
expensive, thus allowing to specify partial resets can speed things up.
Also allow resetting to be initiated from vm_event responses as an
optiomization.
Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>
---
v3: Rebase on simpler approach after dropping empty_p2m feature
v2: address review comments and add more sanity checking
---
tools/include/xenctrl.h | 3 ++-
tools/libs/ctrl/xc_memshr.c | 7 ++++++-
xen/arch/x86/include/asm/mem_sharing.h | 9 +++++++++
xen/arch/x86/mm/mem_sharing.c | 24 +++++++++++++++++++-----
xen/common/vm_event.c | 15 +++++++++++++++
xen/include/public/memory.h | 4 +++-
xen/include/public/vm_event.h | 8 ++++++++
7 files changed, 62 insertions(+), 8 deletions(-)
diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 95bd5eca67..1b089a2c02 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -2290,7 +2290,8 @@ int xc_memshr_fork(xc_interface *xch,
*
* With VMs that have a lot of memory this call may block for a long time.
*/
-int xc_memshr_fork_reset(xc_interface *xch, uint32_t forked_domain);
+int xc_memshr_fork_reset(xc_interface *xch, uint32_t forked_domain,
+ bool reset_state, bool reset_memory);
/* Debug calls: return the number of pages referencing the shared frame backing
* the input argument. Should be one or greater.
diff --git a/tools/libs/ctrl/xc_memshr.c b/tools/libs/ctrl/xc_memshr.c
index a6cfd7dccf..a0d0b894e2 100644
--- a/tools/libs/ctrl/xc_memshr.c
+++ b/tools/libs/ctrl/xc_memshr.c
@@ -257,12 +257,17 @@ int xc_memshr_fork(xc_interface *xch, uint32_t pdomid,
uint32_t domid,
return xc_memshr_memop(xch, domid, &mso);
}
-int xc_memshr_fork_reset(xc_interface *xch, uint32_t domid)
+int xc_memshr_fork_reset(xc_interface *xch, uint32_t domid, bool reset_state,
+ bool reset_memory)
{
xen_mem_sharing_op_t mso;
memset(&mso, 0, sizeof(mso));
mso.op = XENMEM_sharing_op_fork_reset;
+ if ( reset_state )
+ mso.u.fork.flags |= XENMEM_FORK_RESET_STATE;
+ if ( reset_memory )
+ mso.u.fork.flags |= XENMEM_FORK_RESET_MEMORY;
return xc_memshr_memop(xch, domid, &mso);
}
diff --git a/xen/arch/x86/include/asm/mem_sharing.h
b/xen/arch/x86/include/asm/mem_sharing.h
index cf7a12f4d2..2c00069bc9 100644
--- a/xen/arch/x86/include/asm/mem_sharing.h
+++ b/xen/arch/x86/include/asm/mem_sharing.h
@@ -85,6 +85,9 @@ static inline bool mem_sharing_is_fork(const struct domain *d)
int mem_sharing_fork_page(struct domain *d, gfn_t gfn,
bool unsharing);
+int mem_sharing_fork_reset(struct domain *d, bool reset_state,
+ bool reset_memory);
+
/*
* If called by a foreign domain, possible errors are
* -EBUSY -> ring full
@@ -148,6 +151,12 @@ static inline int mem_sharing_fork_page(struct domain *d,
gfn_t gfn, bool lock)
return -EOPNOTSUPP;
}
+static inline int mem_sharing_fork_reset(struct domain *d, bool reset_state,
+ bool reset_memory)
+{
+ return -EOPNOTSUPP;
+}
+
#endif
#endif /* __MEM_SHARING_H__ */
diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index 15e6a7ed81..2f447d94ab 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -1879,15 +1879,21 @@ static int fork(struct domain *cd, struct domain *d)
* footprints the hypercall continuation should be implemented (or if this
* feature needs to be become "stable").
*/
-static int mem_sharing_fork_reset(struct domain *d)
+int mem_sharing_fork_reset(struct domain *d, bool reset_state,
+ bool reset_memory)
{
- int rc;
+ int rc = 0;
struct domain *pd = d->parent;
struct p2m_domain *p2m = p2m_get_hostp2m(d);
struct page_info *page, *tmp;
+ ASSERT(reset_state || reset_memory);
+
domain_pause(d);
+ if ( !reset_memory )
+ goto state;
+
/* need recursive lock because we will free pages */
spin_lock_recursive(&d->page_alloc_lock);
page_list_for_each_safe(page, tmp, &d->page_list)
@@ -1920,7 +1926,9 @@ static int mem_sharing_fork_reset(struct domain *d)
}
spin_unlock_recursive(&d->page_alloc_lock);
- rc = copy_settings(d, pd);
+ state:
+ if ( reset_state )
+ rc = copy_settings(d, pd);
domain_unpause(d);
@@ -2227,15 +2235,21 @@ int
mem_sharing_memop(XEN_GUEST_HANDLE_PARAM(xen_mem_sharing_op_t) arg)
case XENMEM_sharing_op_fork_reset:
{
+ bool reset_state = mso.u.fork.flags & XENMEM_FORK_RESET_STATE;
+ bool reset_memory = mso.u.fork.flags & XENMEM_FORK_RESET_MEMORY;
+
rc = -EINVAL;
- if ( mso.u.fork.pad || mso.u.fork.flags )
+ if ( mso.u.fork.pad || (!reset_state && !reset_memory) )
+ goto out;
+ if ( mso.u.fork.flags &
+ ~(XENMEM_FORK_RESET_STATE | XENMEM_FORK_RESET_MEMORY) )
goto out;
rc = -ENOSYS;
if ( !d->parent )
goto out;
- rc = mem_sharing_fork_reset(d);
+ rc = mem_sharing_fork_reset(d, reset_state, reset_memory);
break;
}
diff --git a/xen/common/vm_event.c b/xen/common/vm_event.c
index 84cf52636b..d26a6699fc 100644
--- a/xen/common/vm_event.c
+++ b/xen/common/vm_event.c
@@ -28,6 +28,11 @@
#include <asm/p2m.h>
#include <asm/monitor.h>
#include <asm/vm_event.h>
+
+#ifdef CONFIG_MEM_SHARING
+#include <asm/mem_sharing.h>
+#endif
+
#include <xsm/xsm.h>
#include <public/hvm/params.h>
@@ -394,6 +399,16 @@ static int vm_event_resume(struct domain *d, struct
vm_event_domain *ved)
if ( rsp.reason == VM_EVENT_REASON_MEM_PAGING )
p2m_mem_paging_resume(d, &rsp);
#endif
+#ifdef CONFIG_MEM_SHARING
+ if ( mem_sharing_is_fork(d) )
+ {
+ bool reset_state = rsp.flags & VM_EVENT_FLAG_RESET_FORK_STATE;
+ bool reset_mem = rsp.flags & VM_EVENT_FLAG_RESET_FORK_MEMORY;
+
+ if ( reset_state || reset_mem )
+ ASSERT(!mem_sharing_fork_reset(d, reset_state, reset_mem));
+ }
+#endif
/*
* Check emulation flags in the arch-specific handler only, as it
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index a1a0f0233a..f8d26fb77d 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -541,12 +541,14 @@ struct xen_mem_sharing_op {
uint32_t gref; /* IN: gref to debug */
} u;
} debug;
- struct mem_sharing_op_fork { /* OP_FORK */
+ struct mem_sharing_op_fork { /* OP_FORK{,_RESET} */
domid_t parent_domain; /* IN: parent's domain id */
/* Only makes sense for short-lived forks */
#define XENMEM_FORK_WITH_IOMMU_ALLOWED (1u << 0)
/* Only makes sense for short-lived forks */
#define XENMEM_FORK_BLOCK_INTERRUPTS (1u << 1)
+#define XENMEM_FORK_RESET_STATE (1u << 2)
+#define XENMEM_FORK_RESET_MEMORY (1u << 3)
uint16_t flags; /* IN: optional settings */
uint32_t pad; /* Must be set to 0 */
} fork;
diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
index bb003d21d0..81c2ee28cc 100644
--- a/xen/include/public/vm_event.h
+++ b/xen/include/public/vm_event.h
@@ -127,6 +127,14 @@
* Reset the vmtrace buffer (if vmtrace is enabled)
*/
#define VM_EVENT_FLAG_RESET_VMTRACE (1 << 13)
+/*
+ * Reset the VM state (if VM is fork)
+ */
+#define VM_EVENT_FLAG_RESET_FORK_STATE (1 << 14)
+/*
+ * Remove unshared entried from physmap (if VM is fork)
+ */
+#define VM_EVENT_FLAG_RESET_FORK_MEMORY (1 << 15)
/*
* Reasons for the vm event request
--
2.25.1
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |