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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] x86/mm: pagetable_dying() is HVM-only
commit 2fb2dee1ac6288349a8a8320cde739df4f0e379f
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 21 10:59:43 2020 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 21 10:59:43 2020 +0200
x86/mm: pagetable_dying() is HVM-only
Its only caller lives in HVM-only code.
This involves wider changes, in order to limit #ifdef-ary: Shadow's
SHOPT_FAST_EMULATION and the fields used by it get constrained to HVM
builds as well. Additionally the shadow_{init,continue}_emulation()
stubs for the !HVM case aren't needed anymore and hence get dropped.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
xen/arch/x86/mm/paging.c | 2 ++
xen/arch/x86/mm/shadow/common.c | 4 +++
xen/arch/x86/mm/shadow/multi.c | 62 +++++++++++++++++++++++-----------------
xen/arch/x86/mm/shadow/private.h | 19 +++---------
xen/include/asm-x86/domain.h | 8 ++++++
xen/include/asm-x86/mm.h | 2 ++
xen/include/asm-x86/paging.h | 2 +-
7 files changed, 56 insertions(+), 43 deletions(-)
diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
index 469bb76429..f5ff5d67a0 100644
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -851,6 +851,7 @@ int paging_enable(struct domain *d, u32 mode)
return shadow_enable(d, mode);
}
+#ifdef CONFIG_HVM
/* Called from the guest to indicate that a process is being torn down
* and therefore its pagetables will soon be discarded */
void pagetable_dying(paddr_t gpa)
@@ -865,6 +866,7 @@ void pagetable_dying(paddr_t gpa)
BUG();
#endif
}
+#endif /* CONFIG_HVM */
/* Print paging-assistance info to the console */
void paging_dump_domain_info(struct domain *d)
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index d899675ebd..ad15803cc8 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -66,7 +66,9 @@ int shadow_domain_init(struct domain *d)
#if (SHADOW_OPTIMIZATIONS & SHOPT_OUT_OF_SYNC)
d->arch.paging.shadow.oos_active = 0;
#endif
+#ifdef CONFIG_HVM
d->arch.paging.shadow.pagetable_dying_op = 0;
+#endif
return 0;
}
@@ -690,8 +692,10 @@ void shadow_promote(struct domain *d, mfn_t gmfn, unsigned
int type)
if ( !test_and_set_bit(_PGC_page_table, &page->count_info) )
{
page->shadow_flags = 0;
+#ifdef CONFIG_HVM
if ( is_hvm_domain(d) )
page->pagetable_dying = false;
+#endif
}
ASSERT(!(page->shadow_flags & (1u << type)));
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index ffb2b87740..16bb6f3e8a 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -2764,8 +2764,10 @@ static int sh_page_fault(struct vcpu *v,
mfn_t gmfn, sl1mfn = _mfn(0);
shadow_l1e_t sl1e, *ptr_sl1e;
paddr_t gpa;
+#ifdef CONFIG_HVM
struct sh_emulate_ctxt emul_ctxt;
const struct x86_emulate_ops *emul_ops;
+#endif
int r;
p2m_type_t p2mt;
uint32_t rc, error_code;
@@ -3253,7 +3255,13 @@ static int sh_page_fault(struct vcpu *v,
* caught by user-mode page-table check above.
*/
emulate_readonly:
+ if ( !is_hvm_domain(d) )
+ {
+ ASSERT_UNREACHABLE();
+ goto not_a_shadow_fault;
+ }
+#ifdef CONFIG_HVM
/* Unshadow if we are writing to a toplevel pagetable that is
* flagged as a dying process, and that is not currently used. */
if ( sh_mfn_is_a_page_table(gmfn) && is_hvm_domain(d) &&
@@ -3302,31 +3310,28 @@ static int sh_page_fault(struct vcpu *v,
#if SHADOW_OPTIMIZATIONS & SHOPT_FAST_EMULATION
early_emulation:
#endif
- if ( is_hvm_domain(d) )
+ /*
+ * If we are in the middle of injecting an exception or interrupt then
+ * we should not emulate: the fault is a side effect of the processor
+ * trying to deliver the exception (e.g. IDT/GDT accesses, pushing the
+ * exception frame onto the stack). Furthermore it is almost
+ * certainly the case the handler stack is currently considered to be
+ * a page table, so we should unshadow the faulting page before
+ * exiting.
+ */
+ if ( unlikely(hvm_event_pending(v)) )
{
- /*
- * If we are in the middle of injecting an exception or interrupt then
- * we should not emulate: the fault is a side effect of the processor
- * trying to deliver the exception (e.g. IDT/GDT accesses, pushing the
- * exception frame onto the stack). Furthermore it is almost
- * certainly the case the handler stack is currently considered to be
- * a page table, so we should unshadow the faulting page before
- * exiting.
- */
- if ( unlikely(hvm_event_pending(v)) )
- {
#if SHADOW_OPTIMIZATIONS & SHOPT_FAST_EMULATION
- if ( fast_emul )
- {
- perfc_incr(shadow_fault_fast_emulate_fail);
- v->arch.paging.last_write_emul_ok = 0;
- }
-#endif
- sh_remove_shadows(d, gmfn, 0 /* thorough */, 1 /* must succeed */);
- trace_shadow_emulate_other(TRC_SHADOW_EMULATE_UNSHADOW_EVTINJ,
- va, gfn);
- return EXCRET_fault_fixed;
+ if ( fast_emul )
+ {
+ perfc_incr(shadow_fault_fast_emulate_fail);
+ v->arch.paging.last_write_emul_ok = 0;
}
+#endif
+ sh_remove_shadows(d, gmfn, 0 /* thorough */, 1 /* must succeed */);
+ trace_shadow_emulate_other(TRC_SHADOW_EMULATE_UNSHADOW_EVTINJ,
+ va, gfn);
+ return EXCRET_fault_fixed;
}
SHADOW_PRINTK("emulate: eip=%#lx esp=%#lx\n", regs->rip, regs->rsp);
@@ -3334,11 +3339,8 @@ static int sh_page_fault(struct vcpu *v,
emul_ops = shadow_init_emulation(&emul_ctxt, regs, GUEST_PTE_SIZE);
r = x86_emulate(&emul_ctxt.ctxt, emul_ops);
-
-#ifdef CONFIG_HVM
if ( r == X86EMUL_EXCEPTION )
{
- ASSERT(is_hvm_domain(d));
/*
* This emulation covers writes to shadow pagetables. We tolerate #PF
* (from accesses spanning pages, concurrent paging updated from
@@ -3360,7 +3362,6 @@ static int sh_page_fault(struct vcpu *v,
r = X86EMUL_UNHANDLEABLE;
}
}
-#endif
/*
* NB. We do not unshadow on X86EMUL_EXCEPTION. It's not clear that it
@@ -3466,6 +3467,7 @@ static int sh_page_fault(struct vcpu *v,
emulate_done:
SHADOW_PRINTK("emulated\n");
return EXCRET_fault_fixed;
+#endif /* CONFIG_HVM */
mmio:
if ( !guest_mode(regs) )
@@ -4166,7 +4168,9 @@ sh_update_cr3(struct vcpu *v, int do_locking, bool
noflush)
int sh_rm_write_access_from_sl1p(struct domain *d, mfn_t gmfn,
mfn_t smfn, unsigned long off)
{
+#ifdef CONFIG_HVM
struct vcpu *curr = current;
+#endif
int r;
shadow_l1e_t *sl1p, sl1e;
struct page_info *sp;
@@ -4174,10 +4178,12 @@ int sh_rm_write_access_from_sl1p(struct domain *d,
mfn_t gmfn,
ASSERT(mfn_valid(gmfn));
ASSERT(mfn_valid(smfn));
+#ifdef CONFIG_HVM
/* Remember if we've been told that this process is being torn down */
if ( curr->domain == d && is_hvm_domain(d) )
curr->arch.paging.shadow.pagetable_dying
= mfn_to_page(gmfn)->pagetable_dying;
+#endif
sp = mfn_to_page(smfn);
@@ -4433,6 +4439,7 @@ int sh_remove_l3_shadow(struct domain *d, mfn_t sl4mfn,
mfn_t sl3mfn)
}
#endif /* 64bit guest */
+#ifdef CONFIG_HVM
/**************************************************************************/
/* Function for the guest to inform us that a process is being torn
* down. We remember that as a hint to unshadow its pagetables soon,
@@ -4554,6 +4561,7 @@ static void sh_pagetable_dying(paddr_t gpa)
put_gfn(d, gpa >> PAGE_SHIFT);
}
#endif
+#endif /* CONFIG_HVM */
/**************************************************************************/
/* Audit tools */
@@ -4887,8 +4895,8 @@ const struct paging_mode sh_paging_mode = {
#if SHADOW_OPTIMIZATIONS & SHOPT_WRITABLE_HEURISTIC
.shadow.guess_wrmap = sh_guess_wrmap,
#endif
-#endif /* CONFIG_HVM */
.shadow.pagetable_dying = sh_pagetable_dying,
+#endif /* CONFIG_HVM */
.shadow.trace_emul_write_val = trace_emulate_write_val,
.shadow.shadow_levels = SHADOW_PAGING_LEVELS,
};
diff --git a/xen/arch/x86/mm/shadow/private.h b/xen/arch/x86/mm/shadow/private.h
index 0044450999..3fd3f0617a 100644
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -66,7 +66,11 @@ extern int shadow_audit_enable;
#define SHOPT_FAST_EMULATION 0x80 /* Fast write emulation */
#define SHOPT_OUT_OF_SYNC 0x100 /* Allow guest writes to L1 PTs */
+#ifdef CONFIG_HVM
#define SHADOW_OPTIMIZATIONS 0x1ff
+#else
+#define SHADOW_OPTIMIZATIONS (0x1ff & ~SHOPT_FAST_EMULATION)
+#endif
/******************************************************************************
@@ -716,26 +720,11 @@ struct sh_emulate_ctxt {
#endif
};
-#ifdef CONFIG_HVM
const struct x86_emulate_ops *shadow_init_emulation(
struct sh_emulate_ctxt *sh_ctxt, struct cpu_user_regs *regs,
unsigned int pte_size);
void shadow_continue_emulation(
struct sh_emulate_ctxt *sh_ctxt, struct cpu_user_regs *regs);
-#else
-static inline const struct x86_emulate_ops *shadow_init_emulation(
- struct sh_emulate_ctxt *sh_ctxt, struct cpu_user_regs *regs,
- unsigned int pte_size)
-{
- BUG();
- return NULL;
-}
-static inline void shadow_continue_emulation(
- struct sh_emulate_ctxt *sh_ctxt, struct cpu_user_regs *regs)
-{
- BUG();
-}
-#endif
/* Stop counting towards early unshadows, as we've seen a real page fault */
static inline void sh_reset_early_unshadow(struct vcpu *v)
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 554b8dddcc..e2294d553f 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -117,8 +117,10 @@ struct shadow_domain {
/* OOS */
bool_t oos_active;
+#ifdef CONFIG_HVM
/* Has this domain ever used HVMOP_pagetable_dying? */
bool_t pagetable_dying_op;
+#endif
#ifdef CONFIG_PV
/* PV L1 Terminal Fault mitigation. */
@@ -137,10 +139,12 @@ struct shadow_vcpu {
unsigned long last_emulated_mfn_for_unshadow;
/* MFN of the last shadow that we shot a writeable mapping in */
unsigned long last_writeable_pte_smfn;
+#ifdef CONFIG_HVM
/* Last frame number that we emulated a write to. */
unsigned long last_emulated_frame;
/* Last MFN that we emulated a write successfully */
unsigned long last_emulated_mfn;
+#endif
/* Shadow out-of-sync: pages that this vcpu has let go out of sync */
mfn_t oos[SHADOW_OOS_PAGES];
@@ -151,8 +155,10 @@ struct shadow_vcpu {
unsigned long off[SHADOW_OOS_FIXUPS];
} oos_fixup[SHADOW_OOS_PAGES];
+#ifdef CONFIG_HVM
bool_t pagetable_dying;
#endif
+#endif
};
/************************************************/
@@ -225,10 +231,12 @@ struct paging_vcpu {
const struct paging_mode *mode;
/* Nested Virtualization: paging mode of nested guest */
const struct paging_mode *nestedmode;
+#ifdef CONFIG_HVM
/* HVM guest: last emulate was to a pagetable */
unsigned int last_write_was_pt:1;
/* HVM guest: last write emulation succeeds */
unsigned int last_write_emul_ok:1;
+#endif
/* Translated guest: virtual TLB */
struct shadow_vtlb *vtlb;
spinlock_t vtlb_lock;
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 1fa334b306..3d3f9d49ac 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -287,7 +287,9 @@ struct page_info
*/
struct {
uint16_t shadow_flags;
+#ifdef CONFIG_HVM
bool pagetable_dying;
+#endif
};
/* When in use as a shadow, next shadow in this hash chain. */
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index 4fb3f09e1a..5243de7312 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -107,8 +107,8 @@ struct shadow_paging_mode {
void (*destroy_monitor_table )(struct vcpu *v, mfn_t mmfn);
int (*guess_wrmap )(struct vcpu *v,
unsigned long vaddr, mfn_t gmfn);
-#endif
void (*pagetable_dying )(paddr_t gpa);
+#endif
void (*trace_emul_write_val )(const void *ptr, unsigned long
vaddr,
const void *src, unsigned int
bytes);
#endif
--
generated by git-patchbot for /home/xen/git/xen.git#master
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