x86/mm: allow for building without shadow mode support Considering the complexity of the code, it seems to be a reasonable thing to allow people to disable that code entirely even outside the immediate need for this by the next patch. Signed-off-by: Jan Beulich --- v2: Set mode table in shadow_vcpu_init() stub. Convert BUG()/BUG_ON() to ASSERT()/ASSERT_UNREACHABLE() and make various of the stub functions macros or inline. Hide opt_dom0_shadow when !CONFIG_SHADOW_PAGING. Adjust Makefile modification. --- a/xen/arch/x86/Rules.mk +++ b/xen/arch/x86/Rules.mk @@ -32,9 +32,13 @@ x86 := y x86_32 := n x86_64 := y +shadow-paging ?= y + CFLAGS += -mno-red-zone -mno-sse -fpic CFLAGS += -fno-asynchronous-unwind-tables # -fvisibility=hidden reduces -fpic cost, if it's available ifneq ($(call cc-option,$(CC),-fvisibility=hidden,n),n) CFLAGS += -DGCC_HAS_VISIBILITY_ATTRIBUTE endif + +CFLAGS-$(shadow-paging) += -DCONFIG_SHADOW_PAGING --- a/xen/arch/x86/domain_build.c +++ b/xen/arch/x86/domain_build.c @@ -128,8 +128,10 @@ struct vcpu *__init alloc_dom0_vcpu0(str return alloc_vcpu(dom0, 0, 0); } +#ifdef CONFIG_SHADOW_PAGING static bool_t __initdata opt_dom0_shadow; boolean_param("dom0_shadow", opt_dom0_shadow); +#endif static char __initdata opt_dom0_ioports_disable[200] = ""; string_param("dom0_ioports_disable", opt_dom0_ioports_disable); @@ -1399,6 +1401,7 @@ int __init construct_dom0( regs->esi = vstartinfo_start; regs->eflags = X86_EFLAGS_IF; +#ifdef CONFIG_SHADOW_PAGING if ( opt_dom0_shadow ) { if ( is_pvh_domain(d) ) @@ -1409,6 +1412,7 @@ int __init construct_dom0( if ( paging_enable(d, PG_SH_enable) == 0 ) paging_update_paging_modes(v); } +#endif /* * PVH Fixme: XENFEAT_supervisor_mode_kernel has been reused in PVH with a --- a/xen/arch/x86/mm/paging.c +++ b/xen/arch/x86/mm/paging.c @@ -635,16 +635,16 @@ int paging_domain_init(struct domain *d, * don't want to leak any active log-dirty bitmaps */ d->arch.paging.log_dirty.top = _mfn(INVALID_MFN); - /* The order of the *_init calls below is important, as the later - * ones may rewrite some common fields. Shadow pagetables are the - * default... */ - shadow_domain_init(d, domcr_flags); - - /* ... but we will use hardware assistance if it's available. */ + /* + * Shadow pagetables are the default, but we will use + * hardware assistance if it's available and enabled. + */ if ( hap_enabled(d) ) hap_domain_init(d); + else + rc = shadow_domain_init(d, domcr_flags); - return 0; + return rc; } /* vcpu paging struct initialization goes here */ @@ -822,12 +822,16 @@ int paging_enable(struct domain *d, u32 * and therefore its pagetables will soon be discarded */ void pagetable_dying(struct domain *d, paddr_t gpa) { +#ifdef CONFIG_SHADOW_PAGING struct vcpu *v; ASSERT(paging_mode_shadow(d)); v = d->vcpu[0]; v->arch.paging.mode->shadow.pagetable_dying(v, gpa); +#else + BUG(); +#endif } /* Print paging-assistance info to the console */ --- a/xen/arch/x86/mm/shadow/Makefile +++ b/xen/arch/x86/mm/shadow/Makefile @@ -1,4 +1,8 @@ -obj-$(x86_64) += common.o guest_2.o guest_3.o guest_4.o +ifeq ($(shadow-paging),y) +obj-y += common.o guest_2.o guest_3.o guest_4.o +else +obj-y += none.o +endif guest_%.o: multi.c Makefile $(CC) $(CFLAGS) -DGUEST_PAGING_LEVELS=$* -c $< -o $@ --- a/xen/arch/x86/mm/shadow/common.c +++ b/xen/arch/x86/mm/shadow/common.c @@ -47,7 +47,7 @@ static void sh_clean_dirty_bitmap(struct /* Set up the shadow-specific parts of a domain struct at start of day. * Called for every domain from arch_domain_create() */ -void shadow_domain_init(struct domain *d, unsigned int domcr_flags) +int shadow_domain_init(struct domain *d, unsigned int domcr_flags) { INIT_PAGE_LIST_HEAD(&d->arch.paging.shadow.freelist); INIT_PAGE_LIST_HEAD(&d->arch.paging.shadow.pinned_shadows); @@ -61,6 +61,8 @@ void shadow_domain_init(struct domain *d d->arch.paging.shadow.oos_off = (domcr_flags & DOMCRF_oos_off) ? 1 : 0; #endif d->arch.paging.shadow.pagetable_dying_op = 0; + + return 0; } /* Setup the shadow-specfic parts of a vcpu struct. Note: The most important --- /dev/null +++ b/xen/arch/x86/mm/shadow/none.c @@ -0,0 +1,78 @@ +#include +#include + +static int _enable_log_dirty(struct domain *d, bool_t log_global) +{ + ASSERT(is_pv_domain(d)); + return -EOPNOTSUPP; +} + +static int _disable_log_dirty(struct domain *d) +{ + ASSERT(is_pv_domain(d)); + return -EOPNOTSUPP; +} + +static void _clean_dirty_bitmap(struct domain *d) +{ + ASSERT(is_pv_domain(d)); +} + +int shadow_domain_init(struct domain *d, unsigned int domcr_flags) +{ + paging_log_dirty_init(d, _enable_log_dirty, + _disable_log_dirty, _clean_dirty_bitmap); + return is_pv_domain(d) ? 0 : -EOPNOTSUPP; +} + +static int _page_fault(struct vcpu *v, unsigned long va, + struct cpu_user_regs *regs) +{ + ASSERT_UNREACHABLE(); + return 0; +} + +static int _invlpg(struct vcpu *v, unsigned long va) +{ + ASSERT_UNREACHABLE(); + return -EOPNOTSUPP; +} + +static unsigned long _gva_to_gfn(struct vcpu *v, struct p2m_domain *p2m, + unsigned long va, uint32_t *pfec) +{ + ASSERT_UNREACHABLE(); + return INVALID_GFN; +} + +static void _update_cr3(struct vcpu *v, int do_locking) +{ + ASSERT_UNREACHABLE(); +} + +static void _update_paging_modes(struct vcpu *v) +{ + ASSERT_UNREACHABLE(); +} + +static void _write_p2m_entry(struct domain *d, unsigned long gfn, + l1_pgentry_t *p, l1_pgentry_t new, + unsigned int level) +{ + ASSERT_UNREACHABLE(); +} + +static const struct paging_mode sh_paging_none = { + .page_fault = _page_fault, + .invlpg = _invlpg, + .gva_to_gfn = _gva_to_gfn, + .update_cr3 = _update_cr3, + .update_paging_modes = _update_paging_modes, + .write_p2m_entry = _write_p2m_entry, +}; + +void shadow_vcpu_init(struct vcpu *v) +{ + ASSERT(is_pv_domain(v->domain)); + v->arch.paging.mode = &sh_paging_none; +} --- a/xen/include/asm-x86/domain.h +++ b/xen/include/asm-x86/domain.h @@ -87,6 +87,7 @@ void hypercall_page_initialise(struct do /* shadow paging extension */ /************************************************/ struct shadow_domain { +#ifdef CONFIG_SHADOW_PAGING unsigned int opt_flags; /* runtime tunable optimizations on/off */ struct page_list_head pinned_shadows; @@ -116,9 +117,11 @@ struct shadow_domain { /* Has this domain ever used HVMOP_pagetable_dying? */ bool_t pagetable_dying_op; +#endif }; struct shadow_vcpu { +#ifdef CONFIG_SHADOW_PAGING /* PAE guests: per-vcpu shadow top-level table */ l3_pgentry_t l3table[4] __attribute__((__aligned__(32))); /* PAE guests: per-vcpu cache of the top-level *guest* entries */ @@ -144,6 +147,7 @@ struct shadow_vcpu { } oos_fixup[SHADOW_OOS_PAGES]; bool_t pagetable_dying; +#endif }; /************************************************/ --- a/xen/include/asm-x86/paging.h +++ b/xen/include/asm-x86/paging.h @@ -39,7 +39,11 @@ #define PG_SH_shift 20 #define PG_HAP_shift 21 /* We're in one of the shadow modes */ +#ifdef CONFIG_SHADOW_PAGING #define PG_SH_enable (1U << PG_SH_shift) +#else +#define PG_SH_enable 0 +#endif #define PG_HAP_enable (1U << PG_HAP_shift) /* common paging mode bits */ @@ -74,6 +78,7 @@ struct sh_emulate_ctxt; struct shadow_paging_mode { +#ifdef CONFIG_SHADOW_PAGING void (*detach_old_tables )(struct vcpu *v); int (*x86_emulate_write )(struct vcpu *v, unsigned long va, void *src, u32 bytes, @@ -88,6 +93,7 @@ struct shadow_paging_mode { int (*guess_wrmap )(struct vcpu *v, unsigned long vaddr, mfn_t gmfn); void (*pagetable_dying )(struct vcpu *v, paddr_t gpa); +#endif /* For outsiders to tell what mode we're in */ unsigned int shadow_levels; }; --- a/xen/include/asm-x86/shadow.h +++ b/xen/include/asm-x86/shadow.h @@ -49,12 +49,14 @@ /* Set up the shadow-specific parts of a domain struct at start of day. * Called from paging_domain_init(). */ -void shadow_domain_init(struct domain *d, unsigned int domcr_flags); +int shadow_domain_init(struct domain *d, unsigned int domcr_flags); /* Setup the shadow-specific parts of a vcpu struct. It is called by * paging_vcpu_init() in paging.c */ void shadow_vcpu_init(struct vcpu *v); +#ifdef CONFIG_SHADOW_PAGING + /* Enable an arbitrary shadow mode. Call once at domain creation. */ int shadow_enable(struct domain *d, u32 mode); @@ -77,17 +79,40 @@ void shadow_teardown(struct domain *d); /* Call once all of the references to the domain have gone away */ void shadow_final_teardown(struct domain *d); -/* Remove all shadows of the guest mfn. */ void sh_remove_shadows(struct vcpu *v, mfn_t gmfn, int fast, int all); + +/* Discard _all_ mappings from the domain's shadows. */ +void shadow_blow_tables_per_domain(struct domain *d); + +#else /* !CONFIG_SHADOW_PAGING */ + +#define shadow_teardown(d) ASSERT(is_pv_domain(d)) +#define shadow_final_teardown(d) ASSERT(is_pv_domain(d)) +#define shadow_enable(d, mode) \ + ({ ASSERT(is_pv_domain(d)); -EOPNOTSUPP; }) +#define shadow_track_dirty_vram(d, begin_pfn, nr, bitmap) \ + ({ ASSERT_UNREACHABLE(); -EOPNOTSUPP; }) + +static inline void sh_remove_shadows(struct vcpu *v, mfn_t gmfn, + bool_t fast, bool_t all) {} + +static inline void shadow_blow_tables_per_domain(struct domain *d) {} + +static inline int shadow_domctl(struct domain *d, xen_domctl_shadow_op_t *sc, + XEN_GUEST_HANDLE_PARAM(void) u_domctl) +{ + return -EINVAL; +} + +#endif /* CONFIG_SHADOW_PAGING */ + +/* Remove all shadows of the guest mfn. */ static inline void shadow_remove_all_shadows(struct vcpu *v, mfn_t gmfn) { /* See the comment about locking in sh_remove_shadows */ sh_remove_shadows(v, gmfn, 0 /* Be thorough */, 1 /* Must succeed */); } -/* Discard _all_ mappings from the domain's shadows. */ -void shadow_blow_tables_per_domain(struct domain *d); - #endif /* _XEN_SHADOW_H */ /* --- a/xen/include/xen/paging.h +++ b/xen/include/xen/paging.h @@ -7,7 +7,7 @@ #include #include -#elif defined CONFIG_SHADOW +#elif defined CONFIG_SHADOW_PAGING #include