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linux/include/xen/interface/xen.h
Jeremy Fitzhardinge e57778a1e3 xen: implement ptep_modify_prot_start/commit 
Xen has a pte update function which will update a pte while preserving
its accessed and dirty bits.  This means that ptep_modify_prot_start() can be
implemented as a simple read of the pte value.  The hardware may
update the pte in the meantime, but ptep_modify_prot_commit() updates it while
preserving any changes that may have happened in the meantime.

The updates in ptep_modify_prot_commit() are batched if we're currently in lazy
mmu mode.

The mmu_update hypercall can take a batch of updates to perform, but
this code doesn't make particular use of that feature, in favour of
using generic multicall batching to get them all into the hypervisor.

The net effect of this is that each mprotect pte update turns from two
expensive trap-and-emulate faults into they hypervisor into a single
hypercall whose cost is amortized in a batched multicall.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-25 15:17:23 +02:00

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/******************************************************************************
* xen.h
*
* Guest OS interface to Xen.
*
* Copyright (c) 2004, K A Fraser
*/
#ifndef __XEN_PUBLIC_XEN_H__
#define __XEN_PUBLIC_XEN_H__
#include <asm/xen/interface.h>
#include <asm/pvclock-abi.h>
/*
* XEN "SYSTEM CALLS" (a.k.a. HYPERCALLS).
*/
/*
* x86_32: EAX = vector; EBX, ECX, EDX, ESI, EDI = args 1, 2, 3, 4, 5.
* EAX = return value
* (argument registers may be clobbered on return)
* x86_64: RAX = vector; RDI, RSI, RDX, R10, R8, R9 = args 1, 2, 3, 4, 5, 6.
* RAX = return value
* (argument registers not clobbered on return; RCX, R11 are)
*/
#define __HYPERVISOR_set_trap_table 0
#define __HYPERVISOR_mmu_update 1
#define __HYPERVISOR_set_gdt 2
#define __HYPERVISOR_stack_switch 3
#define __HYPERVISOR_set_callbacks 4
#define __HYPERVISOR_fpu_taskswitch 5
#define __HYPERVISOR_sched_op 6
#define __HYPERVISOR_dom0_op 7
#define __HYPERVISOR_set_debugreg 8
#define __HYPERVISOR_get_debugreg 9
#define __HYPERVISOR_update_descriptor 10
#define __HYPERVISOR_memory_op 12
#define __HYPERVISOR_multicall 13
#define __HYPERVISOR_update_va_mapping 14
#define __HYPERVISOR_set_timer_op 15
#define __HYPERVISOR_event_channel_op_compat 16
#define __HYPERVISOR_xen_version 17
#define __HYPERVISOR_console_io 18
#define __HYPERVISOR_physdev_op_compat 19
#define __HYPERVISOR_grant_table_op 20
#define __HYPERVISOR_vm_assist 21
#define __HYPERVISOR_update_va_mapping_otherdomain 22
#define __HYPERVISOR_iret 23 /* x86 only */
#define __HYPERVISOR_vcpu_op 24
#define __HYPERVISOR_set_segment_base 25 /* x86/64 only */
#define __HYPERVISOR_mmuext_op 26
#define __HYPERVISOR_acm_op 27
#define __HYPERVISOR_nmi_op 28
#define __HYPERVISOR_sched_op_new 29
#define __HYPERVISOR_callback_op 30
#define __HYPERVISOR_xenoprof_op 31
#define __HYPERVISOR_event_channel_op 32
#define __HYPERVISOR_physdev_op 33
#define __HYPERVISOR_hvm_op 34
/* Architecture-specific hypercall definitions. */
#define __HYPERVISOR_arch_0 48
#define __HYPERVISOR_arch_1 49
#define __HYPERVISOR_arch_2 50
#define __HYPERVISOR_arch_3 51
#define __HYPERVISOR_arch_4 52
#define __HYPERVISOR_arch_5 53
#define __HYPERVISOR_arch_6 54
#define __HYPERVISOR_arch_7 55
/*
* VIRTUAL INTERRUPTS
*
* Virtual interrupts that a guest OS may receive from Xen.
*/
#define VIRQ_TIMER 0 /* Timebase update, and/or requested timeout. */
#define VIRQ_DEBUG 1 /* Request guest to dump debug info. */
#define VIRQ_CONSOLE 2 /* (DOM0) Bytes received on emergency console. */
#define VIRQ_DOM_EXC 3 /* (DOM0) Exceptional event for some domain. */
#define VIRQ_DEBUGGER 6 /* (DOM0) A domain has paused for debugging. */
/* Architecture-specific VIRQ definitions. */
#define VIRQ_ARCH_0 16
#define VIRQ_ARCH_1 17
#define VIRQ_ARCH_2 18
#define VIRQ_ARCH_3 19
#define VIRQ_ARCH_4 20
#define VIRQ_ARCH_5 21
#define VIRQ_ARCH_6 22
#define VIRQ_ARCH_7 23
#define NR_VIRQS 24
/*
* MMU-UPDATE REQUESTS
*
* HYPERVISOR_mmu_update() accepts a list of (ptr, val) pairs.
* A foreigndom (FD) can be specified (or DOMID_SELF for none).
* Where the FD has some effect, it is described below.
* ptr[1:0] specifies the appropriate MMU_* command.
*
* ptr[1:0] == MMU_NORMAL_PT_UPDATE:
* Updates an entry in a page table. If updating an L1 table, and the new
* table entry is valid/present, the mapped frame must belong to the FD, if
* an FD has been specified. If attempting to map an I/O page then the
* caller assumes the privilege of the FD.
* FD == DOMID_IO: Permit /only/ I/O mappings, at the priv level of the caller.
* FD == DOMID_XEN: Map restricted areas of Xen's heap space.
* ptr[:2] -- Machine address of the page-table entry to modify.
* val -- Value to write.
*
* ptr[1:0] == MMU_MACHPHYS_UPDATE:
* Updates an entry in the machine->pseudo-physical mapping table.
* ptr[:2] -- Machine address within the frame whose mapping to modify.
* The frame must belong to the FD, if one is specified.
* val -- Value to write into the mapping entry.
*
* ptr[1:0] == MMU_PT_UPDATE_PRESERVE_AD:
* As MMU_NORMAL_PT_UPDATE above, but A/D bits currently in the PTE are ORed
* with those in @val.
*/
#define MMU_NORMAL_PT_UPDATE 0 /* checked '*ptr = val'. ptr is MA. */
#define MMU_MACHPHYS_UPDATE 1 /* ptr = MA of frame to modify entry for */
#define MMU_PT_UPDATE_PRESERVE_AD 2 /* atomically: *ptr = val | (*ptr&(A|D)) */
/*
* MMU EXTENDED OPERATIONS
*
* HYPERVISOR_mmuext_op() accepts a list of mmuext_op structures.
* A foreigndom (FD) can be specified (or DOMID_SELF for none).
* Where the FD has some effect, it is described below.
*
* cmd: MMUEXT_(UN)PIN_*_TABLE
* mfn: Machine frame number to be (un)pinned as a p.t. page.
* The frame must belong to the FD, if one is specified.
*
* cmd: MMUEXT_NEW_BASEPTR
* mfn: Machine frame number of new page-table base to install in MMU.
*
* cmd: MMUEXT_NEW_USER_BASEPTR [x86/64 only]
* mfn: Machine frame number of new page-table base to install in MMU
* when in user space.
*
* cmd: MMUEXT_TLB_FLUSH_LOCAL
* No additional arguments. Flushes local TLB.
*
* cmd: MMUEXT_INVLPG_LOCAL
* linear_addr: Linear address to be flushed from the local TLB.
*
* cmd: MMUEXT_TLB_FLUSH_MULTI
* vcpumask: Pointer to bitmap of VCPUs to be flushed.
*
* cmd: MMUEXT_INVLPG_MULTI
* linear_addr: Linear address to be flushed.
* vcpumask: Pointer to bitmap of VCPUs to be flushed.
*
* cmd: MMUEXT_TLB_FLUSH_ALL
* No additional arguments. Flushes all VCPUs' TLBs.
*
* cmd: MMUEXT_INVLPG_ALL
* linear_addr: Linear address to be flushed from all VCPUs' TLBs.
*
* cmd: MMUEXT_FLUSH_CACHE
* No additional arguments. Writes back and flushes cache contents.
*
* cmd: MMUEXT_SET_LDT
* linear_addr: Linear address of LDT base (NB. must be page-aligned).
* nr_ents: Number of entries in LDT.
*/
#define MMUEXT_PIN_L1_TABLE 0
#define MMUEXT_PIN_L2_TABLE 1
#define MMUEXT_PIN_L3_TABLE 2
#define MMUEXT_PIN_L4_TABLE 3
#define MMUEXT_UNPIN_TABLE 4
#define MMUEXT_NEW_BASEPTR 5
#define MMUEXT_TLB_FLUSH_LOCAL 6
#define MMUEXT_INVLPG_LOCAL 7
#define MMUEXT_TLB_FLUSH_MULTI 8
#define MMUEXT_INVLPG_MULTI 9
#define MMUEXT_TLB_FLUSH_ALL 10
#define MMUEXT_INVLPG_ALL 11
#define MMUEXT_FLUSH_CACHE 12
#define MMUEXT_SET_LDT 13
#define MMUEXT_NEW_USER_BASEPTR 15
#ifndef __ASSEMBLY__
struct mmuext_op {
unsigned int cmd;
union {
/* [UN]PIN_TABLE, NEW_BASEPTR, NEW_USER_BASEPTR */
unsigned long mfn;
/* INVLPG_LOCAL, INVLPG_ALL, SET_LDT */
unsigned long linear_addr;
} arg1;
union {
/* SET_LDT */
unsigned int nr_ents;
/* TLB_FLUSH_MULTI, INVLPG_MULTI */
void *vcpumask;
} arg2;
};
DEFINE_GUEST_HANDLE_STRUCT(mmuext_op);
#endif
/* These are passed as 'flags' to update_va_mapping. They can be ORed. */
/* When specifying UVMF_MULTI, also OR in a pointer to a CPU bitmap. */
/* UVMF_LOCAL is merely UVMF_MULTI with a NULL bitmap pointer. */
#define UVMF_NONE (0UL<<0) /* No flushing at all. */
#define UVMF_TLB_FLUSH (1UL<<0) /* Flush entire TLB(s). */
#define UVMF_INVLPG (2UL<<0) /* Flush only one entry. */
#define UVMF_FLUSHTYPE_MASK (3UL<<0)
#define UVMF_MULTI (0UL<<2) /* Flush subset of TLBs. */
#define UVMF_LOCAL (0UL<<2) /* Flush local TLB. */
#define UVMF_ALL (1UL<<2) /* Flush all TLBs. */
/*
* Commands to HYPERVISOR_console_io().
*/
#define CONSOLEIO_write 0
#define CONSOLEIO_read 1
/*
* Commands to HYPERVISOR_vm_assist().
*/
#define VMASST_CMD_enable 0
#define VMASST_CMD_disable 1
#define VMASST_TYPE_4gb_segments 0
#define VMASST_TYPE_4gb_segments_notify 1
#define VMASST_TYPE_writable_pagetables 2
#define VMASST_TYPE_pae_extended_cr3 3
#define MAX_VMASST_TYPE 3
#ifndef __ASSEMBLY__
typedef uint16_t domid_t;
/* Domain ids >= DOMID_FIRST_RESERVED cannot be used for ordinary domains. */
#define DOMID_FIRST_RESERVED (0x7FF0U)
/* DOMID_SELF is used in certain contexts to refer to oneself. */
#define DOMID_SELF (0x7FF0U)
/*
* DOMID_IO is used to restrict page-table updates to mapping I/O memory.
* Although no Foreign Domain need be specified to map I/O pages, DOMID_IO
* is useful to ensure that no mappings to the OS's own heap are accidentally
* installed. (e.g., in Linux this could cause havoc as reference counts
* aren't adjusted on the I/O-mapping code path).
* This only makes sense in MMUEXT_SET_FOREIGNDOM, but in that context can
* be specified by any calling domain.
*/
#define DOMID_IO (0x7FF1U)
/*
* DOMID_XEN is used to allow privileged domains to map restricted parts of
* Xen's heap space (e.g., the machine_to_phys table).
* This only makes sense in MMUEXT_SET_FOREIGNDOM, and is only permitted if
* the caller is privileged.
*/
#define DOMID_XEN (0x7FF2U)
/*
* Send an array of these to HYPERVISOR_mmu_update().
* NB. The fields are natural pointer/address size for this architecture.
*/
struct mmu_update {
uint64_t ptr; /* Machine address of PTE. */
uint64_t val; /* New contents of PTE. */
};
DEFINE_GUEST_HANDLE_STRUCT(mmu_update);
/*
* Send an array of these to HYPERVISOR_multicall().
* NB. The fields are natural register size for this architecture.
*/
struct multicall_entry {
unsigned long op;
long result;
unsigned long args[6];
};
DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);
/*
* Event channel endpoints per domain:
* 1024 if a long is 32 bits; 4096 if a long is 64 bits.
*/
#define NR_EVENT_CHANNELS (sizeof(unsigned long) * sizeof(unsigned long) * 64)
struct vcpu_time_info {
/*
* Updates to the following values are preceded and followed
* by an increment of 'version'. The guest can therefore
* detect updates by looking for changes to 'version'. If the
* least-significant bit of the version number is set then an
* update is in progress and the guest must wait to read a
* consistent set of values. The correct way to interact with
* the version number is similar to Linux's seqlock: see the
* implementations of read_seqbegin/read_seqretry.
*/
uint32_t version;
uint32_t pad0;
uint64_t tsc_timestamp; /* TSC at last update of time vals. */
uint64_t system_time; /* Time, in nanosecs, since boot. */
/*
* Current system time:
* system_time + ((tsc - tsc_timestamp) << tsc_shift) * tsc_to_system_mul
* CPU frequency (Hz):
* ((10^9 << 32) / tsc_to_system_mul) >> tsc_shift
*/
uint32_t tsc_to_system_mul;
int8_t tsc_shift;
int8_t pad1[3];
}; /* 32 bytes */
struct vcpu_info {
/*
* 'evtchn_upcall_pending' is written non-zero by Xen to indicate
* a pending notification for a particular VCPU. It is then cleared
* by the guest OS /before/ checking for pending work, thus avoiding
* a set-and-check race. Note that the mask is only accessed by Xen
* on the CPU that is currently hosting the VCPU. This means that the
* pending and mask flags can be updated by the guest without special
* synchronisation (i.e., no need for the x86 LOCK prefix).
* This may seem suboptimal because if the pending flag is set by
* a different CPU then an IPI may be scheduled even when the mask
* is set. However, note:
* 1. The task of 'interrupt holdoff' is covered by the per-event-
* channel mask bits. A 'noisy' event that is continually being
* triggered can be masked at source at this very precise
* granularity.
* 2. The main purpose of the per-VCPU mask is therefore to restrict
* reentrant execution: whether for concurrency control, or to
* prevent unbounded stack usage. Whatever the purpose, we expect
* that the mask will be asserted only for short periods at a time,
* and so the likelihood of a 'spurious' IPI is suitably small.
* The mask is read before making an event upcall to the guest: a
* non-zero mask therefore guarantees that the VCPU will not receive
* an upcall activation. The mask is cleared when the VCPU requests
* to block: this avoids wakeup-waiting races.
*/
uint8_t evtchn_upcall_pending;
uint8_t evtchn_upcall_mask;
unsigned long evtchn_pending_sel;
struct arch_vcpu_info arch;
struct pvclock_vcpu_time_info time;
}; /* 64 bytes (x86) */
/*
* Xen/kernel shared data -- pointer provided in start_info.
* NB. We expect that this struct is smaller than a page.
*/
struct shared_info {
struct vcpu_info vcpu_info[MAX_VIRT_CPUS];
/*
* A domain can create "event channels" on which it can send and receive
* asynchronous event notifications. There are three classes of event that
* are delivered by this mechanism:
* 1. Bi-directional inter- and intra-domain connections. Domains must
* arrange out-of-band to set up a connection (usually by allocating
* an unbound 'listener' port and avertising that via a storage service
* such as xenstore).
* 2. Physical interrupts. A domain with suitable hardware-access
* privileges can bind an event-channel port to a physical interrupt
* source.
* 3. Virtual interrupts ('events'). A domain can bind an event-channel
* port to a virtual interrupt source, such as the virtual-timer
* device or the emergency console.
*
* Event channels are addressed by a "port index". Each channel is
* associated with two bits of information:
* 1. PENDING -- notifies the domain that there is a pending notification
* to be processed. This bit is cleared by the guest.
* 2. MASK -- if this bit is clear then a 0->1 transition of PENDING
* will cause an asynchronous upcall to be scheduled. This bit is only
* updated by the guest. It is read-only within Xen. If a channel
* becomes pending while the channel is masked then the 'edge' is lost
* (i.e., when the channel is unmasked, the guest must manually handle
* pending notifications as no upcall will be scheduled by Xen).
*
* To expedite scanning of pending notifications, any 0->1 pending
* transition on an unmasked channel causes a corresponding bit in a
* per-vcpu selector word to be set. Each bit in the selector covers a
* 'C long' in the PENDING bitfield array.
*/
unsigned long evtchn_pending[sizeof(unsigned long) * 8];
unsigned long evtchn_mask[sizeof(unsigned long) * 8];
/*
* Wallclock time: updated only by control software. Guests should base
* their gettimeofday() syscall on this wallclock-base value.
*/
struct pvclock_wall_clock wc;
struct arch_shared_info arch;
};
/*
* Start-of-day memory layout for the initial domain (DOM0):
* 1. The domain is started within contiguous virtual-memory region.
* 2. The contiguous region begins and ends on an aligned 4MB boundary.
* 3. The region start corresponds to the load address of the OS image.
* If the load address is not 4MB aligned then the address is rounded down.
* 4. This the order of bootstrap elements in the initial virtual region:
* a. relocated kernel image
* b. initial ram disk [mod_start, mod_len]
* c. list of allocated page frames [mfn_list, nr_pages]
* d. start_info_t structure [register ESI (x86)]
* e. bootstrap page tables [pt_base, CR3 (x86)]
* f. bootstrap stack [register ESP (x86)]
* 5. Bootstrap elements are packed together, but each is 4kB-aligned.
* 6. The initial ram disk may be omitted.
* 7. The list of page frames forms a contiguous 'pseudo-physical' memory
* layout for the domain. In particular, the bootstrap virtual-memory
* region is a 1:1 mapping to the first section of the pseudo-physical map.
* 8. All bootstrap elements are mapped read-writable for the guest OS. The
* only exception is the bootstrap page table, which is mapped read-only.
* 9. There is guaranteed to be at least 512kB padding after the final
* bootstrap element. If necessary, the bootstrap virtual region is
* extended by an extra 4MB to ensure this.
*/
#define MAX_GUEST_CMDLINE 1024
struct start_info {
/* THE FOLLOWING ARE FILLED IN BOTH ON INITIAL BOOT AND ON RESUME. */
char magic[32]; /* "xen-<version>-<platform>". */
unsigned long nr_pages; /* Total pages allocated to this domain. */
unsigned long shared_info; /* MACHINE address of shared info struct. */
uint32_t flags; /* SIF_xxx flags. */
unsigned long store_mfn; /* MACHINE page number of shared page. */
uint32_t store_evtchn; /* Event channel for store communication. */
union {
struct {
unsigned long mfn; /* MACHINE page number of console page. */
uint32_t evtchn; /* Event channel for console page. */
} domU;
struct {
uint32_t info_off; /* Offset of console_info struct. */
uint32_t info_size; /* Size of console_info struct from start.*/
} dom0;
} console;
/* THE FOLLOWING ARE ONLY FILLED IN ON INITIAL BOOT (NOT RESUME). */
unsigned long pt_base; /* VIRTUAL address of page directory. */
unsigned long nr_pt_frames; /* Number of bootstrap p.t. frames. */
unsigned long mfn_list; /* VIRTUAL address of page-frame list. */
unsigned long mod_start; /* VIRTUAL address of pre-loaded module. */
unsigned long mod_len; /* Size (bytes) of pre-loaded module. */
int8_t cmd_line[MAX_GUEST_CMDLINE];
};
/* These flags are passed in the 'flags' field of start_info_t. */
#define SIF_PRIVILEGED (1<<0) /* Is the domain privileged? */
#define SIF_INITDOMAIN (1<<1) /* Is this the initial control domain? */
typedef uint64_t cpumap_t;
typedef uint8_t xen_domain_handle_t[16];
/* Turn a plain number into a C unsigned long constant. */
#define __mk_unsigned_long(x) x ## UL
#define mk_unsigned_long(x) __mk_unsigned_long(x)
#else /* __ASSEMBLY__ */
/* In assembly code we cannot use C numeric constant suffixes. */
#define mk_unsigned_long(x) x
#endif /* !__ASSEMBLY__ */
#endif /* __XEN_PUBLIC_XEN_H__ */
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