117 lines
4.0 KiB
C
117 lines
4.0 KiB
C
/* Things the lguest guest needs to know. Note: like all lguest interfaces,
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* this is subject to wild and random change between versions. */
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#ifndef _ASM_LGUEST_H
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#define _ASM_LGUEST_H
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#ifndef __ASSEMBLY__
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#include <asm/irq.h>
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#define LHCALL_FLUSH_ASYNC 0
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#define LHCALL_LGUEST_INIT 1
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#define LHCALL_CRASH 2
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#define LHCALL_LOAD_GDT 3
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#define LHCALL_NEW_PGTABLE 4
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#define LHCALL_FLUSH_TLB 5
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#define LHCALL_LOAD_IDT_ENTRY 6
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#define LHCALL_SET_STACK 7
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#define LHCALL_TS 8
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#define LHCALL_SET_CLOCKEVENT 9
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#define LHCALL_HALT 10
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#define LHCALL_BIND_DMA 12
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#define LHCALL_SEND_DMA 13
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#define LHCALL_SET_PTE 14
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#define LHCALL_SET_PMD 15
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#define LHCALL_LOAD_TLS 16
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#define LG_CLOCK_MIN_DELTA 100UL
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#define LG_CLOCK_MAX_DELTA ULONG_MAX
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/*G:031 First, how does our Guest contact the Host to ask for privileged
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* operations? There are two ways: the direct way is to make a "hypercall",
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* to make requests of the Host Itself.
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*
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* Our hypercall mechanism uses the highest unused trap code (traps 32 and
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* above are used by real hardware interrupts). Seventeen hypercalls are
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* available: the hypercall number is put in the %eax register, and the
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* arguments (when required) are placed in %edx, %ebx and %ecx. If a return
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* value makes sense, it's returned in %eax.
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*
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* Grossly invalid calls result in Sudden Death at the hands of the vengeful
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* Host, rather than returning failure. This reflects Winston Churchill's
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* definition of a gentleman: "someone who is only rude intentionally". */
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#define LGUEST_TRAP_ENTRY 0x1F
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static inline unsigned long
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hcall(unsigned long call,
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unsigned long arg1, unsigned long arg2, unsigned long arg3)
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{
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/* "int" is the Intel instruction to trigger a trap. */
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asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
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/* The call is in %eax (aka "a"), and can be replaced */
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: "=a"(call)
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/* The other arguments are in %eax, %edx, %ebx & %ecx */
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: "a"(call), "d"(arg1), "b"(arg2), "c"(arg3)
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/* "memory" means this might write somewhere in memory.
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* This isn't true for all calls, but it's safe to tell
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* gcc that it might happen so it doesn't get clever. */
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: "memory");
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return call;
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}
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/*:*/
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void async_hcall(unsigned long call,
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unsigned long arg1, unsigned long arg2, unsigned long arg3);
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/* Can't use our min() macro here: needs to be a constant */
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#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32)
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#define LHCALL_RING_SIZE 64
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struct hcall_ring
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{
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u32 eax, edx, ebx, ecx;
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};
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/*G:032 The second method of communicating with the Host is to via "struct
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* lguest_data". The Guest's very first hypercall is to tell the Host where
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* this is, and then the Guest and Host both publish information in it. :*/
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struct lguest_data
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{
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/* 512 == enabled (same as eflags in normal hardware). The Guest
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* changes interrupts so often that a hypercall is too slow. */
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unsigned int irq_enabled;
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/* Fine-grained interrupt disabling by the Guest */
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DECLARE_BITMAP(blocked_interrupts, LGUEST_IRQS);
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/* The Host writes the virtual address of the last page fault here,
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* which saves the Guest a hypercall. CR2 is the native register where
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* this address would normally be found. */
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unsigned long cr2;
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/* Wallclock time set by the Host. */
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struct timespec time;
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/* Async hypercall ring. Instead of directly making hypercalls, we can
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* place them in here for processing the next time the Host wants.
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* This batching can be quite efficient. */
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/* 0xFF == done (set by Host), 0 == pending (set by Guest). */
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u8 hcall_status[LHCALL_RING_SIZE];
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/* The actual registers for the hypercalls. */
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struct hcall_ring hcalls[LHCALL_RING_SIZE];
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/* Fields initialized by the Host at boot: */
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/* Memory not to try to access */
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unsigned long reserve_mem;
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/* ID of this Guest (used by network driver to set ethernet address) */
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u16 guestid;
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/* KHz for the TSC clock. */
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u32 tsc_khz;
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/* Fields initialized by the Guest at boot: */
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/* Instruction range to suppress interrupts even if enabled */
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unsigned long noirq_start, noirq_end;
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};
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extern struct lguest_data lguest_data;
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_LGUEST_H */
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