![Rusty Russell](/assets/img/avatar_default.png)
Took some cycles to re-read the Lguest Journey end-to-end, fix some rot and tighten some phrases. Only comments change. No new jokes, but a couple of recycled old jokes. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
73 lines
2.4 KiB
C
73 lines
2.4 KiB
C
/* Architecture specific portion of the lguest hypercalls */
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#ifndef _X86_LGUEST_HCALL_H
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#define _X86_LGUEST_HCALL_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_SHUTDOWN 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_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 LHCALL_NOTIFY 17
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#define LGUEST_TRAP_ENTRY 0x1F
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/* Argument number 3 to LHCALL_LGUEST_SHUTDOWN */
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#define LGUEST_SHUTDOWN_POWEROFF 1
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#define LGUEST_SHUTDOWN_RESTART 2
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#ifndef __ASSEMBLY__
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#include <asm/hw_irq.h>
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/*G:031 But 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). Fifteen 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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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 in %eax (aka "a") might be overwritten */
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: "=a"(call)
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/* The 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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/* 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_args
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{
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/* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */
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unsigned long arg0, arg2, arg3, arg1;
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};
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#endif /* !__ASSEMBLY__ */
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#endif /* _I386_LGUEST_HCALL_H */
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