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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 06/24] x86/pv: Implement pv_inject_{event, page_fault, hw_exception}()
To help with event injection improvements for the PV uses of x86_emulate(),
implement a event injection API which matches its hvm counterpart.
This is started with taking do_guest_trap() and modifying its calling API to
pv_inject_event(), subsequentally implementing the former in terms of the
latter.
The existing propagate_page_fault() is fairly similar to
pv_inject_page_fault(), although it has a return value. Only a single caller
makes use of the return value, and non-NULL is only returned if the passed cr2
is non-canonical. Opencode this single case in
handle_gdt_ldt_mapping_fault(), allowing propagate_page_fault() to become
void.
The call to reserved_bit_page_fault() in propagate_page_fault() was
conceptually wrong to start with. Complaining about reserved bits should be
part of handling the pagefault itself, not part of injecting a pagefault into
the guest. It is therefore moved ahead of the injection call in
do_page_fault() to compensate.
The remaining #PF specific bits are moved into pv_inject_event(), and
pv_inject_page_fault() is implemented as a static inline wrapper.
No practical change from a guests point of view.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
v3:
* Reposition reserved_bit_page_fault() handling
v2:
* New
---
xen/arch/x86/mm.c | 5 +-
xen/arch/x86/mm/shadow/common.c | 4 +-
xen/arch/x86/traps.c | 147 ++++++++++++++++++++--------------------
xen/include/asm-x86/domain.h | 26 +++++++
xen/include/asm-x86/mm.h | 1 -
5 files changed, 104 insertions(+), 79 deletions(-)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d365f59..b7c7122 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5136,7 +5136,7 @@ static int ptwr_emulated_read(
if ( !__addr_ok(addr) ||
(rc = __copy_from_user(p_data, (void *)addr, bytes)) )
{
- propagate_page_fault(addr + bytes - rc, 0); /* read fault */
+ pv_inject_page_fault(0, addr + bytes - rc); /* Read fault. */
return X86EMUL_EXCEPTION;
}
@@ -5177,7 +5177,8 @@ static int ptwr_emulated_update(
addr &= ~(sizeof(paddr_t)-1);
if ( (rc = copy_from_user(&full, (void *)addr, sizeof(paddr_t))) != 0 )
{
- propagate_page_fault(addr+sizeof(paddr_t)-rc, 0); /* read fault */
+ pv_inject_page_fault(0, /* Read fault. */
+ addr + sizeof(paddr_t) - rc);
return X86EMUL_EXCEPTION;
}
/* Mask out bits provided by caller. */
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index a4a3c4b..f07803b 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -323,7 +323,7 @@ pv_emulate_read(enum x86_segment seg,
if ( (rc = copy_from_user(p_data, (void *)offset, bytes)) != 0 )
{
- propagate_page_fault(offset + bytes - rc, 0); /* read fault */
+ pv_inject_page_fault(0, offset + bytes - rc); /* Read fault. */
return X86EMUL_EXCEPTION;
}
@@ -1723,7 +1723,7 @@ static mfn_t emulate_gva_to_mfn(struct vcpu *v, unsigned
long vaddr,
if ( is_hvm_vcpu(v) )
hvm_inject_page_fault(pfec, vaddr);
else
- propagate_page_fault(vaddr, pfec);
+ pv_inject_page_fault(pfec, vaddr);
return _mfn(BAD_GVA_TO_GFN);
}
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index b464211..195d590 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -625,37 +625,75 @@ void fatal_trap(const struct cpu_user_regs *regs, bool_t
show_remote)
(regs->eflags & X86_EFLAGS_IF) ? "" : ", IN INTERRUPT CONTEXT");
}
-static void do_guest_trap(unsigned int trapnr,
- const struct cpu_user_regs *regs)
+void pv_inject_event(const struct x86_event *event)
{
struct vcpu *v = current;
+ struct cpu_user_regs *regs = guest_cpu_user_regs();
struct trap_bounce *tb;
const struct trap_info *ti;
+ const uint8_t vector = event->vector;
const bool use_error_code =
- ((trapnr < 32) && (TRAP_HAVE_EC & (1u << trapnr)));
+ ((vector < 32) && (TRAP_HAVE_EC & (1u << vector)));
+ unsigned int error_code = event->error_code;
- trace_pv_trap(trapnr, regs->eip, use_error_code, regs->error_code);
+ ASSERT(vector == event->vector); /* Confirm no truncation. */
+ if ( use_error_code )
+ ASSERT(error_code != X86_EVENT_NO_EC);
+ else
+ ASSERT(error_code == X86_EVENT_NO_EC);
tb = &v->arch.pv_vcpu.trap_bounce;
- ti = &v->arch.pv_vcpu.trap_ctxt[trapnr];
+ ti = &v->arch.pv_vcpu.trap_ctxt[vector];
tb->flags = TBF_EXCEPTION;
tb->cs = ti->cs;
tb->eip = ti->address;
+ if ( vector == TRAP_page_fault )
+ {
+ v->arch.pv_vcpu.ctrlreg[2] = event->cr2;
+ arch_set_cr2(v, event->cr2);
+
+ /* Re-set error_code.user flag appropriately for the guest. */
+ error_code &= ~PFEC_user_mode;
+ if ( !guest_kernel_mode(v, regs) )
+ error_code |= PFEC_user_mode;
+
+ trace_pv_page_fault(event->cr2, error_code);
+ }
+ else
+ trace_pv_trap(vector, regs->eip, use_error_code, error_code);
+
if ( use_error_code )
{
tb->flags |= TBF_EXCEPTION_ERRCODE;
- tb->error_code = regs->error_code;
+ tb->error_code = error_code;
}
if ( TI_GET_IF(ti) )
tb->flags |= TBF_INTERRUPT;
if ( unlikely(null_trap_bounce(v, tb)) )
+ {
gprintk(XENLOG_WARNING,
"Unhandled %s fault/trap [#%d, ec=%04x]\n",
- trapstr(trapnr), trapnr, regs->error_code);
+ trapstr(vector), vector, error_code);
+
+ if ( vector == TRAP_page_fault )
+ show_page_walk(event->cr2);
+ }
+}
+
+static inline void do_guest_trap(unsigned int trapnr,
+ const struct cpu_user_regs *regs)
+{
+ const struct x86_event event = {
+ .vector = trapnr,
+ .error_code = (((trapnr < 32) && (TRAP_HAVE_EC & (1u << trapnr)))
+ ? regs->error_code : X86_EVENT_NO_EC),
+ };
+
+ pv_inject_event(&event);
}
static void instruction_done(
@@ -1289,7 +1327,7 @@ static int emulate_invalid_rdtscp(struct cpu_user_regs
*regs)
eip = regs->eip;
if ( (rc = copy_from_user(opcode, (char *)eip, sizeof(opcode))) != 0 )
{
- propagate_page_fault(eip + sizeof(opcode) - rc, 0);
+ pv_inject_page_fault(0, eip + sizeof(opcode) - rc);
return EXCRET_fault_fixed;
}
if ( memcmp(opcode, "\xf\x1\xf9", sizeof(opcode)) )
@@ -1310,7 +1348,7 @@ static int emulate_forced_invalid_op(struct cpu_user_regs
*regs)
/* Check for forced emulation signature: ud2 ; .ascii "xen". */
if ( (rc = copy_from_user(sig, (char *)eip, sizeof(sig))) != 0 )
{
- propagate_page_fault(eip + sizeof(sig) - rc, 0);
+ pv_inject_page_fault(0, eip + sizeof(sig) - rc);
return EXCRET_fault_fixed;
}
if ( memcmp(sig, "\xf\xbxen", sizeof(sig)) )
@@ -1320,7 +1358,7 @@ static int emulate_forced_invalid_op(struct cpu_user_regs
*regs)
/* We only emulate CPUID. */
if ( ( rc = copy_from_user(instr, (char *)eip, sizeof(instr))) != 0 )
{
- propagate_page_fault(eip + sizeof(instr) - rc, 0);
+ pv_inject_page_fault(0, eip + sizeof(instr) - rc);
return EXCRET_fault_fixed;
}
if ( memcmp(instr, "\xf\xa2", sizeof(instr)) )
@@ -1487,53 +1525,6 @@ static void reserved_bit_page_fault(
show_execution_state(regs);
}
-struct trap_bounce *propagate_page_fault(unsigned long addr, u16 error_code)
-{
- struct trap_info *ti;
- struct vcpu *v = current;
- struct trap_bounce *tb = &v->arch.pv_vcpu.trap_bounce;
-
- if ( unlikely(!is_canonical_address(addr)) )
- {
- ti = &v->arch.pv_vcpu.trap_ctxt[TRAP_gp_fault];
- tb->flags = TBF_EXCEPTION | TBF_EXCEPTION_ERRCODE;
- tb->error_code = 0;
- tb->cs = ti->cs;
- tb->eip = ti->address;
- if ( TI_GET_IF(ti) )
- tb->flags |= TBF_INTERRUPT;
- return tb;
- }
-
- v->arch.pv_vcpu.ctrlreg[2] = addr;
- arch_set_cr2(v, addr);
-
- /* Re-set error_code.user flag appropriately for the guest. */
- error_code &= ~PFEC_user_mode;
- if ( !guest_kernel_mode(v, guest_cpu_user_regs()) )
- error_code |= PFEC_user_mode;
-
- trace_pv_page_fault(addr, error_code);
-
- ti = &v->arch.pv_vcpu.trap_ctxt[TRAP_page_fault];
- tb->flags = TBF_EXCEPTION | TBF_EXCEPTION_ERRCODE;
- tb->error_code = error_code;
- tb->cs = ti->cs;
- tb->eip = ti->address;
- if ( TI_GET_IF(ti) )
- tb->flags |= TBF_INTERRUPT;
- if ( unlikely(null_trap_bounce(v, tb)) )
- {
- printk("%pv: unhandled page fault (ec=%04X)\n", v, error_code);
- show_page_walk(addr);
- }
-
- if ( unlikely(error_code & PFEC_reserved_bit) )
- reserved_bit_page_fault(addr, guest_cpu_user_regs());
-
- return NULL;
-}
-
static int handle_gdt_ldt_mapping_fault(
unsigned long offset, struct cpu_user_regs *regs)
{
@@ -1565,17 +1556,22 @@ static int handle_gdt_ldt_mapping_fault(
}
else
{
- struct trap_bounce *tb;
-
/* In hypervisor mode? Leave it to the #PF handler to fix up. */
if ( !guest_mode(regs) )
return 0;
- /* In guest mode? Propagate fault to guest, with adjusted %cr2. */
- tb = propagate_page_fault(curr->arch.pv_vcpu.ldt_base + offset,
- regs->error_code);
- if ( tb )
- tb->error_code = (offset & ~(X86_XEC_EXT | X86_XEC_IDT)) |
- X86_XEC_TI;
+
+ /* Access would have become non-canonical? Pass #GP[sel] back. */
+ if ( unlikely(!is_canonical_address(
+ curr->arch.pv_vcpu.ldt_base + offset)) )
+ {
+ uint16_t ec = (offset & ~(X86_XEC_EXT | X86_XEC_IDT)) |
X86_XEC_TI;
+
+ pv_inject_hw_exception(TRAP_gp_fault, ec);
+ }
+ else
+ /* else pass the #PF back, with adjusted %cr2. */
+ pv_inject_page_fault(regs->error_code,
+ curr->arch.pv_vcpu.ldt_base + offset);
}
}
else
@@ -1858,7 +1854,10 @@ void do_page_fault(struct cpu_user_regs *regs)
return;
}
- propagate_page_fault(addr, regs->error_code);
+ if ( unlikely(regs->error_code & PFEC_reserved_bit) )
+ reserved_bit_page_fault(addr, regs);
+
+ pv_inject_page_fault(regs->error_code, addr);
}
/*
@@ -2788,7 +2787,7 @@ int pv_emul_cpuid(unsigned int *eax, unsigned int *ebx,
unsigned int *ecx,
goto fail; \
if ( (_rc = copy_from_user(&_x, (type *)_ptr, sizeof(_x))) != 0 ) \
{ \
- propagate_page_fault(_ptr + sizeof(_x) - _rc, 0); \
+ pv_inject_page_fault(0, _ptr + sizeof(_x) - _rc); \
goto skip; \
} \
(eip) += sizeof(_x); _x; })
@@ -2953,8 +2952,8 @@ static int emulate_privileged_op(struct cpu_user_regs
*regs)
if ( (rc = copy_to_user((void *)data_base + rd_ad(edi),
&data, op_bytes)) != 0 )
{
- propagate_page_fault(data_base + rd_ad(edi) + op_bytes - rc,
- PFEC_write_access);
+ pv_inject_page_fault(PFEC_write_access,
+ data_base + rd_ad(edi) + op_bytes - rc);
return EXCRET_fault_fixed;
}
wr_ad(edi, regs->edi + (int)((regs->eflags & X86_EFLAGS_DF)
@@ -2971,8 +2970,8 @@ static int emulate_privileged_op(struct cpu_user_regs
*regs)
if ( (rc = copy_from_user(&data, (void *)data_base + rd_ad(esi),
op_bytes)) != 0 )
{
- propagate_page_fault(data_base + rd_ad(esi)
- + op_bytes - rc, 0);
+ pv_inject_page_fault(0, data_base + rd_ad(esi)
+ + op_bytes - rc);
return EXCRET_fault_fixed;
}
guest_io_write(port, op_bytes, data, currd);
@@ -3529,8 +3528,8 @@ static void emulate_gate_op(struct cpu_user_regs *regs)
rc = __put_user(item, stkp); \
if ( rc ) \
{ \
- propagate_page_fault((unsigned long)(stkp + 1) - rc, \
- PFEC_write_access); \
+ pv_inject_page_fault(PFEC_write_access, \
+ (unsigned long)(stkp + 1) - rc); \
return; \
} \
} while ( 0 )
@@ -3597,7 +3596,7 @@ static void emulate_gate_op(struct cpu_user_regs *regs)
rc = __get_user(parm, ustkp);
if ( rc )
{
- propagate_page_fault((unsigned long)(ustkp + 1) - rc,
0);
+ pv_inject_page_fault(0, (unsigned long)(ustkp + 1) -
rc);
return;
}
push(parm);
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index f6a40eb..39cc658 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -8,6 +8,7 @@
#include <asm/hvm/domain.h>
#include <asm/e820.h>
#include <asm/mce.h>
+#include <asm/x86_emulate.h>
#include <public/vcpu.h>
#include <public/hvm/hvm_info_table.h>
@@ -632,6 +633,31 @@ static inline void free_vcpu_guest_context(struct
vcpu_guest_context *vgc)
struct vcpu_hvm_context;
int arch_set_info_hvm_guest(struct vcpu *v, const struct vcpu_hvm_context
*ctx);
+void pv_inject_event(const struct x86_event *event);
+
+static inline void pv_inject_hw_exception(unsigned int vector, int errcode)
+{
+ const struct x86_event event = {
+ .vector = vector,
+ .type = X86_EVENTTYPE_HW_EXCEPTION,
+ .error_code = errcode,
+ };
+
+ pv_inject_event(&event);
+}
+
+static inline void pv_inject_page_fault(int errcode, unsigned long cr2)
+{
+ const struct x86_event event = {
+ .vector = TRAP_page_fault,
+ .type = X86_EVENTTYPE_HW_EXCEPTION,
+ .error_code = errcode,
+ .cr2 = cr2,
+ };
+
+ pv_inject_event(&event);
+}
+
#endif /* __ASM_DOMAIN_H__ */
/*
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 1b4d1c3..a15029c 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -539,7 +539,6 @@ int new_guest_cr3(unsigned long pfn);
void make_cr3(struct vcpu *v, unsigned long mfn);
void update_cr3(struct vcpu *v);
int vcpu_destroy_pagetables(struct vcpu *);
-struct trap_bounce *propagate_page_fault(unsigned long addr, u16 error_code);
void *do_page_walk(struct vcpu *v, unsigned long addr);
int __sync_local_execstate(void);
--
2.1.4
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