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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [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@xxxxxxxxx> 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); Attachment:
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