diff options
Diffstat (limited to 'include')
-rw-r--r-- | include/asm-x86/lguest_hcall.h | 16 | ||||
-rw-r--r-- | include/linux/lguest.h | 4 | ||||
-rw-r--r-- | include/linux/lguest_launcher.h | 6 |
3 files changed, 15 insertions, 11 deletions
diff --git a/include/asm-x86/lguest_hcall.h b/include/asm-x86/lguest_hcall.h index f948491eb56..9c5092b6aa9 100644 --- a/include/asm-x86/lguest_hcall.h +++ b/include/asm-x86/lguest_hcall.h @@ -18,12 +18,17 @@ #define LHCALL_LOAD_TLS 16 #define LHCALL_NOTIFY 17 +#define LGUEST_TRAP_ENTRY 0x1F + +#ifndef __ASSEMBLY__ +#include <asm/hw_irq.h> + /*G:031 First, how does our Guest contact the Host to ask for privileged * operations? There are two ways: the direct way is to make a "hypercall", * to make requests of the Host Itself. * * Our hypercall mechanism uses the highest unused trap code (traps 32 and - * above are used by real hardware interrupts). Seventeen hypercalls are + * above are used by real hardware interrupts). Fifteen hypercalls are * available: the hypercall number is put in the %eax register, and the * arguments (when required) are placed in %edx, %ebx and %ecx. If a return * value makes sense, it's returned in %eax. @@ -31,20 +36,15 @@ * Grossly invalid calls result in Sudden Death at the hands of the vengeful * Host, rather than returning failure. This reflects Winston Churchill's * definition of a gentleman: "someone who is only rude intentionally". */ -#define LGUEST_TRAP_ENTRY 0x1F - -#ifndef __ASSEMBLY__ -#include <asm/hw_irq.h> - static inline unsigned long hcall(unsigned long call, unsigned long arg1, unsigned long arg2, unsigned long arg3) { /* "int" is the Intel instruction to trigger a trap. */ asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY) - /* The call is in %eax (aka "a"), and can be replaced */ + /* The call in %eax (aka "a") might be overwritten */ : "=a"(call) - /* The other arguments are in %eax, %edx, %ebx & %ecx */ + /* The arguments are in %eax, %edx, %ebx & %ecx */ : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3) /* "memory" means this might write somewhere in memory. * This isn't true for all calls, but it's safe to tell diff --git a/include/linux/lguest.h b/include/linux/lguest.h index 8beb2913462..175e63f4a8c 100644 --- a/include/linux/lguest.h +++ b/include/linux/lguest.h @@ -12,8 +12,8 @@ #define LG_CLOCK_MAX_DELTA ULONG_MAX /*G:032 The second method of communicating with the Host is to via "struct - * lguest_data". The Guest's very first hypercall is to tell the Host where - * this is, and then the Guest and Host both publish information in it. :*/ + * lguest_data". Once the Guest's initialization hypercall tells the Host where + * this is, the Guest and Host both publish information in it. :*/ struct lguest_data { /* 512 == enabled (same as eflags in normal hardware). The Guest diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h index c41fd483af3..697104da91f 100644 --- a/include/linux/lguest_launcher.h +++ b/include/linux/lguest_launcher.h @@ -10,7 +10,11 @@ * real devices (think of the damage it could do!) we provide virtual devices. * We could emulate a PCI bus with various devices on it, but that is a fairly * complex burden for the Host and suboptimal for the Guest, so we have our own - * "lguest" bus and simple drivers. + * simple lguest bus and we use "virtio" drivers. These drivers need a set of + * routines from us which will actually do the virtual I/O, but they handle all + * the net/block/console stuff themselves. This means that if we want to add + * a new device, we simply need to write a new virtio driver and create support + * for it in the Launcher: this code won't need to change. * * Devices are described by a simplified ID, a status byte, and some "config" * bytes which describe this device's configuration. This is placed by the |