Joe Epstein
2011-Jan-06 03:53 UTC
[Xen-devel] [PATCH 2 of 7] REDO2: mem_access & mem_access 2: mem event additions for access
* Adds an ACCESS memory event type, with RESUME as the action.
* Refactors the bits in the memory event to store whether the memory event
was a read, write, or execute (for access memory events only). I used
bits sparingly to keep the structure somewhat the same size.
* Modified VMX to report the needed information in its nested page fault.
SVM is not implemented in this patch series.
Signed-off-by: Joe Epstein <jepstein98@gmail.com>
diff -r cae1ccf5857b -r 253cc5185fb5 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c Wed Jan 05 18:44:56 2011 -0800
+++ b/tools/xenpaging/xenpaging.c Wed Jan 05 18:49:34 2011 -0800
@@ -658,7 +658,7 @@ int main(int argc, char *argv[])
{
DPRINTF("page already populated (domain = %d; vcpu =
%d;"
" p2mt = %x;"
- " gfn = %"PRIx64"; paused =
%"PRId64")\n",
+ " gfn = %"PRIx64"; paused = %d)\n",
paging->mem_event.domain_id, req.vcpu_id,
req.p2mt,
req.gfn, req.flags & MEM_EVENT_FLAG_VCPU_PAUSED);
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/arch/x86/hvm/hvm.c Wed Jan 05 18:49:34 2011 -0800
@@ -61,6 +61,8 @@
#include <public/hvm/ioreq.h>
#include <public/version.h>
#include <public/memory.h>
+#include <asm/mem_event.h>
+#include <public/mem_event.h>
bool_t __read_mostly hvm_enabled;
@@ -1086,14 +1088,66 @@ void hvm_triple_fault(void)
domain_shutdown(v->domain, SHUTDOWN_reboot);
}
-bool_t hvm_hap_nested_page_fault(unsigned long gfn)
+bool_t hvm_hap_nested_page_fault(unsigned long gpa,
+ bool_t gla_valid,
+ unsigned long gla,
+ bool_t access_valid,
+ bool_t access_r,
+ bool_t access_w,
+ bool_t access_x)
{
+ unsigned long gfn = gpa >> PAGE_SHIFT;
p2m_type_t p2mt;
+ p2m_access_t p2ma;
mfn_t mfn;
struct vcpu *v = current;
struct p2m_domain *p2m = p2m_get_hostp2m(v->domain);
- mfn = gfn_to_mfn_guest(p2m, gfn, &p2mt);
+ p2m_lock(p2m);
+ mfn = p2m->get_entry(p2m, gfn, &p2mt, &p2ma, p2m_guest);
+ p2m_unlock(p2m);
+
+ /* Check access permissions first, then handle faults */
+ if ( access_valid && (mfn_x(mfn) != INVALID_MFN) )
+ {
+ int violation = 0;
+ /* If the access is against the permissions, then send to mem_event
*/
+ switch (p2ma)
+ {
+ case p2m_access_n:
+ default:
+ violation = access_r || access_w || access_x;
+ break;
+ case p2m_access_r:
+ violation = access_w || access_x;
+ break;
+ case p2m_access_w:
+ violation = access_r || access_x;
+ break;
+ case p2m_access_x:
+ violation = access_r || access_w;
+ break;
+ case p2m_access_rx:
+ case p2m_access_rx2rw:
+ violation = access_w;
+ break;
+ case p2m_access_wx:
+ violation = access_r;
+ break;
+ case p2m_access_rw:
+ violation = access_x;
+ break;
+ case p2m_access_rwx:
+ break;
+ }
+
+ if ( violation )
+ {
+ p2m_mem_access_check(gpa, gla_valid, gla, access_r, access_w,
access_x);
+
+ return 1;
+ }
+ }
/*
* If this GFN is emulated MMIO or marked as read-only, pass the fault
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/arch/x86/hvm/svm/svm.c Wed Jan 05 18:49:34 2011 -0800
@@ -979,7 +979,7 @@ static void svm_do_nested_pgfault(paddr_
__trace_var(TRC_HVM_NPF, 0, sizeof(_d), &_d);
}
- if ( hvm_hap_nested_page_fault(gfn) )
+ if ( hvm_hap_nested_page_fault(gpa, 0, ~0ull, 0, 0, 0, 0) )
return;
/* Everything else is an error. */
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/arch/x86/hvm/vmx/vmx.c Wed Jan 05 18:49:34 2011 -0800
@@ -2079,7 +2079,14 @@ static void ept_handle_violation(unsigne
__trace_var(TRC_HVM_NPF, 0, sizeof(_d), &_d);
}
- if ( hvm_hap_nested_page_fault(gfn) )
+ if ( hvm_hap_nested_page_fault(gpa,
+ qualification & EPT_GLA_VALID ? 1
: 0,
+ qualification & EPT_GLA_VALID
+ ? __vmread(GUEST_LINEAR_ADDRESS) :
~0ull,
+ 1, /* access types are as follows */
+ qualification & EPT_READ_VIOLATION ? 1
: 0,
+ qualification & EPT_WRITE_VIOLATION ? 1
: 0,
+ qualification & EPT_EXEC_VIOLATION ? 1
: 0) )
return;
/* Everything else is an error. */
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/mm/Makefile
--- a/xen/arch/x86/mm/Makefile Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/arch/x86/mm/Makefile Wed Jan 05 18:49:34 2011 -0800
@@ -9,6 +9,7 @@ obj-$(x86_64) += guest_walk_4.o
obj-$(x86_64) += mem_event.o
obj-$(x86_64) += mem_paging.o
obj-$(x86_64) += mem_sharing.o
+obj-$(x86_64) += mem_access.o
guest_walk_%.o: guest_walk.c Makefile
$(CC) $(CFLAGS) -DGUEST_PAGING_LEVELS=$* -c $< -o $@
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/mm/mem_access.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/arch/x86/mm/mem_access.c Wed Jan 05 18:49:34 2011 -0800
@@ -0,0 +1,59 @@
+/******************************************************************************
+ * arch/x86/mm/mem_access.c
+ *
+ * Memory access support.
+ *
+ * Copyright (c) 2011 Virtuata, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA
+ */
+
+
+#include <asm/p2m.h>
+#include <asm/mem_event.h>
+
+
+int mem_access_domctl(struct domain *d, xen_domctl_mem_event_op_t *mec,
+ XEN_GUEST_HANDLE(void) u_domctl)
+{
+ int rc;
+ struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+ switch( mec->op )
+ {
+ case XEN_DOMCTL_MEM_EVENT_OP_ACCESS_RESUME:
+ {
+ p2m_mem_access_resume(p2m);
+ rc = 0;
+ }
+ break;
+
+ default:
+ rc = -ENOSYS;
+ break;
+ }
+
+ return rc;
+}
+
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/mm/mem_event.c
--- a/xen/arch/x86/mm/mem_event.c Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/arch/x86/mm/mem_event.c Wed Jan 05 18:49:34 2011 -0800
@@ -26,6 +26,7 @@
#include <asm/p2m.h>
#include <asm/mem_event.h>
#include <asm/mem_paging.h>
+#include <asm/mem_access.h>
/* for public/io/ring.h macros */
#define xen_mb() mb()
@@ -67,6 +68,9 @@ static int mem_event_enable(struct domai
mem_event_ring_lock_init(d);
+ /* Wake any VCPUs paused for memory events */
+ mem_event_unpause_vcpus(d);
+
return 0;
err_shared:
@@ -143,12 +147,21 @@ void mem_event_unpause_vcpus(struct doma
vcpu_wake(v);
}
+void mem_event_mark_and_pause(struct vcpu *v)
+{
+ set_bit(_VPF_mem_event, &v->pause_flags);
+ vcpu_sleep_nosync(v);
+}
+
int mem_event_check_ring(struct domain *d)
{
struct vcpu *curr = current;
int free_requests;
int ring_full;
+ if ( !d->mem_event.ring_page )
+ return -1;
+
mem_event_ring_lock(d);
free_requests = RING_FREE_REQUESTS(&d->mem_event.front_ring);
@@ -157,7 +170,7 @@ int mem_event_check_ring(struct domain *
gdprintk(XENLOG_INFO, "free request slots: %d\n",
free_requests);
WARN_ON(free_requests == 0);
}
- ring_full = free_requests < MEM_EVENT_RING_THRESHOLD;
+ ring_full = free_requests < MEM_EVENT_RING_THRESHOLD ? 1 : 0;
if ( (curr->domain->domain_id == d->domain_id) &&
ring_full )
{
@@ -203,7 +216,11 @@ int mem_event_domctl(struct domain *d, x
return rc;
#endif
- if ( mec->mode == 0 )
+ rc = -ENOSYS;
+
+ switch ( mec-> mode )
+ {
+ case 0:
{
switch( mec->op )
{
@@ -268,13 +285,18 @@ int mem_event_domctl(struct domain *d, x
rc = -ENOSYS;
break;
}
+ break;
}
- else
+ case XEN_DOMCTL_MEM_EVENT_OP_PAGING:
{
- rc = -ENOSYS;
-
- if ( mec->mode & XEN_DOMCTL_MEM_EVENT_OP_PAGING )
- rc = mem_paging_domctl(d, mec, u_domctl);
+ rc = mem_paging_domctl(d, mec, u_domctl);
+ break;
+ }
+ case XEN_DOMCTL_MEM_EVENT_OP_ACCESS:
+ {
+ rc = mem_access_domctl(d, mec, u_domctl);
+ break;
+ }
}
return rc;
diff -r cae1ccf5857b -r 253cc5185fb5 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/arch/x86/mm/p2m.c Wed Jan 05 18:49:34 2011 -0800
@@ -2858,6 +2858,97 @@ void p2m_mem_paging_resume(struct p2m_do
}
#endif /* __x86_64__ */
+void p2m_mem_access_check(unsigned long gpa, bool_t gla_valid, unsigned
long gla,
+ bool_t access_r, bool_t access_w, bool_t
access_x)
+{
+ struct vcpu *v = current;
+ mem_event_request_t req;
+ unsigned long gfn = gpa >> PAGE_SHIFT;
+ struct domain *d = v->domain;
+ struct p2m_domain* p2m = p2m_get_hostp2m(d);
+ int res;
+ mfn_t mfn;
+ p2m_type_t p2mt;
+ p2m_access_t p2ma;
+
+ /* First, handle rx2rw conversion automatically */
+ p2m_lock(p2m);
+ mfn = p2m->get_entry(p2m, gfn, &p2mt, &p2ma, p2m_query);
+
+ if ( access_w && p2ma == p2m_access_rx2rw )
+ {
+ p2m->set_entry(p2m, gfn, mfn, 0, p2mt, p2m_access_rw);
+ p2m_unlock(p2m);
+ return;
+ }
+ p2m_unlock(p2m);
+
+ /* Otherwise, check if there is a memory event listener, and send the
message along */
+ res = mem_event_check_ring(d);
+ if ( res < 0 )
+ {
+ /* No listener */
+ if ( p2m->access_required )
+ {
+ printk(XENLOG_INFO
+ "Memory access permissions failure, no mem_event
listener: pausing VCPU %d, dom %d\n",
+ v->vcpu_id, d->domain_id);
+
+ mem_event_mark_and_pause(v);
+ }
+ else
+ {
+ /* A listener is not required, so clear the access restrictions
*/
+ p2m_lock(p2m);
+ p2m->set_entry(p2m, gfn, mfn, 0, p2mt, p2m_access_rwx);
+ p2m_unlock(p2m);
+ }
+
+ return;
+ }
+ else if ( res > 0 )
+ return; /* No space in buffer; VCPU paused */
+
+ memset(&req, 0, sizeof(req));
+ req.type = MEM_EVENT_TYPE_ACCESS;
+ req.reason = MEM_EVENT_REASON_VIOLATION;
+
+ /* Pause the current VCPU unconditionally */
+ vcpu_pause_nosync(v);
+ req.flags |= MEM_EVENT_FLAG_VCPU_PAUSED;
+
+ /* Send request to mem event */
+ req.gfn = gfn;
+ req.offset = gpa & ((1 << PAGE_SHIFT) - 1);
+ req.gla_valid = gla_valid;
+ req.gla = gla;
+ req.access_r = access_r;
+ req.access_w = access_w;
+ req.access_x = access_x;
+
+ req.vcpu_id = v->vcpu_id;
+
+ mem_event_put_request(d, &req);
+
+ /* VCPU paused, mem event request sent */
+}
+
+void p2m_mem_access_resume(struct p2m_domain *p2m)
+{
+ struct domain *d = p2m->domain;
+ mem_event_response_t rsp;
+
+ mem_event_get_response(d, &rsp);
+
+ /* Unpause domain */
+ if ( rsp.flags & MEM_EVENT_FLAG_VCPU_PAUSED )
+ vcpu_unpause(d->vcpu[rsp.vcpu_id]);
+
+ /* Unpause any domains that were paused because the ring was full or no
listener
+ * was available */
+ mem_event_unpause_vcpus(d);
+}
+
/*
* Local variables:
* mode: C
diff -r cae1ccf5857b -r 253cc5185fb5 xen/include/asm-x86/hvm/hvm.h
--- a/xen/include/asm-x86/hvm/hvm.h Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/include/asm-x86/hvm/hvm.h Wed Jan 05 18:49:34 2011 -0800
@@ -356,7 +356,12 @@ static inline void hvm_set_info_guest(st
int hvm_debug_op(struct vcpu *v, int32_t op);
-bool_t hvm_hap_nested_page_fault(unsigned long gfn);
+bool_t hvm_hap_nested_page_fault(unsigned long gpa,
+ bool_t gla_valid, unsigned long gla,
+ bool_t access_valid,
+ bool_t access_r,
+ bool_t access_w,
+ bool_t access_x);
#define hvm_msr_tsc_aux(v) ({
\
struct domain *__d = (v)->domain;
\
diff -r cae1ccf5857b -r 253cc5185fb5 xen/include/asm-x86/mem_access.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/include/asm-x86/mem_access.h Wed Jan 05 18:49:34 2011 -0800
@@ -0,0 +1,35 @@
+/******************************************************************************
+ * include/asm-x86/mem_paging.h
+ *
+ * Memory access support.
+ *
+ * Copyright (c) 2011 Virtuata, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA
+ */
+
+
+int mem_access_domctl(struct domain *d, xen_domctl_mem_event_op_t *mec,
+ XEN_GUEST_HANDLE(void) u_domctl);
+
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff -r cae1ccf5857b -r 253cc5185fb5 xen/include/asm-x86/mem_event.h
--- a/xen/include/asm-x86/mem_event.h Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/include/asm-x86/mem_event.h Wed Jan 05 18:49:34 2011 -0800
@@ -24,6 +24,8 @@
#ifndef __MEM_EVENT_H__
#define __MEM_EVENT_H__
+/* Pauses VCPU while marking pause flag for mem event */
+void mem_event_mark_and_pause(struct vcpu *v);
int mem_event_check_ring(struct domain *d);
void mem_event_put_request(struct domain *d, mem_event_request_t *req);
void mem_event_get_response(struct domain *d, mem_event_response_t *rsp);
diff -r cae1ccf5857b -r 253cc5185fb5 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/include/asm-x86/p2m.h Wed Jan 05 18:49:34 2011 -0800
@@ -522,6 +522,13 @@ static inline void p2m_mem_paging_popula
{ }
#endif
+/* Send mem event based on the access (gla is -1ull if not available).
Handles
+ * the rw2rx conversion */
+void p2m_mem_access_check(unsigned long gpa, bool_t gla_valid, unsigned
long gla,
+ bool_t access_r, bool_t access_w, bool_t
access_x);
+/* Resumes the running of the VCPU, restarting the last instruction */
+void p2m_mem_access_resume(struct p2m_domain *p2m);
+
struct page_info *p2m_alloc_ptp(struct p2m_domain *p2m, unsigned long
type);
#endif /* _XEN_P2M_H */
diff -r cae1ccf5857b -r 253cc5185fb5 xen/include/public/domctl.h
--- a/xen/include/public/domctl.h Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/include/public/domctl.h Wed Jan 05 18:49:34 2011 -0800
@@ -714,7 +714,7 @@ struct xen_domctl_gdbsx_domstatus {
/*
* Page memory in and out.
*/
-#define XEN_DOMCTL_MEM_EVENT_OP_PAGING (1 << 0)
+#define XEN_DOMCTL_MEM_EVENT_OP_PAGING 1
/* Domain memory paging */
#define XEN_DOMCTL_MEM_EVENT_OP_PAGING_NOMINATE 0
@@ -722,6 +722,19 @@ struct xen_domctl_gdbsx_domstatus {
#define XEN_DOMCTL_MEM_EVENT_OP_PAGING_PREP 2
#define XEN_DOMCTL_MEM_EVENT_OP_PAGING_RESUME 3
+/*
+ * Access permissions.
+ *
+ * There are HVM hypercalls to set the per-page access permissions of every
+ * page in a domain. When one of these permissions--independent, read,
+ * write, and execute--is violated, the VCPU is paused and a memory event
+ * is sent with what happened. (See public/mem_event.h) The memory event
+ * handler can then resume the VCPU and redo the access with an
+ * ACCESS_RESUME mode for the following domctl.
+ */
+#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS 2
+#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS_RESUME 0
+
struct xen_domctl_mem_event_op {
uint32_t op; /* XEN_DOMCTL_MEM_EVENT_OP_* */
uint32_t mode; /* XEN_DOMCTL_MEM_EVENT_ENABLE_* */
diff -r cae1ccf5857b -r 253cc5185fb5 xen/include/public/mem_event.h
--- a/xen/include/public/mem_event.h Wed Jan 05 18:44:56 2011 -0800
+++ b/xen/include/public/mem_event.h Wed Jan 05 18:49:34 2011 -0800
@@ -26,18 +26,40 @@
#include "xen.h"
#include "io/ring.h"
+/* Memory event type */
+#define MEM_EVENT_TYPE_SHARED 0
+#define MEM_EVENT_TYPE_PAGING 1
+#define MEM_EVENT_TYPE_ACCESS 2
+
/* Memory event flags */
#define MEM_EVENT_FLAG_VCPU_PAUSED (1 << 0)
+/* Reasons for the memory event request */
+#define MEM_EVENT_REASON_UNKNOWN 0 /* typical reason */
+#define MEM_EVENT_REASON_VIOLATION 1 /* access violation, GFN is
address */
+
typedef struct mem_event_shared_page {
uint32_t port;
} mem_event_shared_page_t;
typedef struct mem_event_st {
+ uint16_t type;
+ uint16_t flags;
+ uint32_t vcpu_id;
+
uint64_t gfn;
+ uint64_t offset;
+ uint64_t gla; /* if gla_valid */
+
uint32_t p2mt;
- uint32_t vcpu_id;
- uint64_t flags;
+
+ uint16_t access_r:1;
+ uint16_t access_w:1;
+ uint16_t access_x:1;
+ uint16_t gla_valid:1;
+ uint16_t available:12;
+
+ uint16_t reason;
} mem_event_request_t, mem_event_response_t;
DEFINE_RING_TYPES(mem_event, mem_event_request_t, mem_event_response_t);
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