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From: | Struan Bartlett |
Subject: | [patch] Re: [Qemu-devel] Suggestion - trap window-close of VM |
Date: | Mon, 28 Mar 2005 13:34:08 +0200 |
User-agent: | Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20041007 Debian/1.7.3-5 |
Hi, I've attached a patch against the 2005-03-26 snapshot that implements two '-on-quit' options for the emulator window: ignore-unless-halted and suspend-unless-halted, that aim to make it safe to allow naive users to (try to) close the VM window by trapping requests to shutdown and either ignoring them or forcing a save of the VM state before obeying them. Caveat: I'll come clean straight away that the patch is implemented using a nasty TARGET_i386-specific hack that detects whether the guest operating system has permanently halted by looking to see if the last instruction executed was 0xF4 and, if so, whether the IF flag is cleared. Saying that, this system appears to work reasonably well on my Pentium host running a Windows 2000 guest, but I have not tested it on any other systems. Usage: 1. If you provide naive users with a variation on the following command line, then you can let your naive users (try to) close the VM window as much as they like. Unless the guest has permanently halted, attempts to close the VM window should save the VM state to 'suspended.qemu' in the current working directory before qemu exits. The same command line will restart the VM where it left off. Then, once the guest has permanently halted, qemu will delete the suspended.qemu file so that the next launch of qemu will boot afresh: qemu -hda win2k.raw -m 64 -monitor null -loadvm suspended.qemu -on-quit suspend-unless-halted 2. Alternatively, the following command will make qemu ignore the user's request to close the emulator window unless the guest has already permanently halted: qemu -hda win2k.raw -m 64 -monitor null -on-quit ignore-unless-halted 3. If you combine this with a test of whether qemu is already running, then it should be safe to let naive users try to both launch and to close qemu as much as they like. e.g. killall -0 qemu 2>/dev/null; if [ $? == 1 ]; then qemu -hda win2k.raw -m 64 -monitor null -loadvm suspended.qemu -on-quit suspend-unless-halted; fi & 4. Finally, if your leave out the -on-quit option altogether, then qemu's behaviour should remain completely unchanged. I hope this is useful for some i386/W2K users out there. Any constructive criticism appreciated. If you know how I could improve permanent halt detection (that doesn't require in-depth knowledge of APM or ACPI) then please let me know. Struan Struan Bartlett wrote:
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--- qemu-snapshot-2005-03-26_23/vl.c Sun Mar 13 17:59:37 2005 +++ qemu-snapshot-2005-03-26_23-on-quit/vl.c Mon Mar 28 02:06:52 2005 @@ -139,6 +139,9 @@ int graphic_height = 600; int graphic_depth = 15; int full_screen = 0; +#ifdef TARGET_I386 +int on_quit = 0; +#endif TextConsole *vga_console; CharDriverState *serial_hds[MAX_SERIAL_PORTS]; CharDriverState *parallel_hds[MAX_PARALLEL_PORTS]; @@ -2675,6 +2678,17 @@ qemu_get_clock(rt_clock)); } +#ifdef TARGET_I386 +int ishalted() { + uint8_t buf[16]; + uint64_t v; + + cpu_memory_rw_debug(cpu_single_env, cpu_single_env->eip-1, buf, 16, 0); + v = ldub_raw(buf); + return (v == 0xf4) && ( !(cpu_single_env->eflags & 0x200) ); +} +#endif + int main_loop(void) { int ret, timeout; @@ -2684,9 +2698,16 @@ if (vm_running) { ret = cpu_exec(env); if (shutdown_requested) { +#ifdef TARGET_I386 + if( on_quit == 0 || on_quit == 2 || ( on_quit == 1 && ishalted() ) ) { +#endif ret = EXCP_INTERRUPT; break; } +#ifdef TARGET_I386 + shutdown_requested = 0; + } +#endif if (reset_requested) { reset_requested = 0; qemu_system_reset(); @@ -2783,6 +2804,11 @@ "-std-vga simulate a standard VGA card with VESA Bochs Extensions\n" " (default is CL-GD5446 PCI VGA)\n" #endif +#ifdef TARGET_I386 + "-on-quit [ignore-unless-halted|suspend-unless-halted]\n" + " select the behaviour when the emulator window is asked to quit\n" + " (default is none)\n" +#endif "-loadvm file start right away with a saved state (loadvm in monitor)\n" "\n" "During emulation, the following keys are useful:\n" @@ -2864,6 +2890,10 @@ QEMU_OPTION_full_screen, QEMU_OPTION_pidfile, QEMU_OPTION_no_kqemu, + +#ifdef TARGET_I386 + QEMU_OPTION_on_quit +#endif }; typedef struct QEMUOption { @@ -2932,6 +2962,9 @@ { "loadvm", HAS_ARG, QEMU_OPTION_loadvm }, { "full-screen", 0, QEMU_OPTION_full_screen }, { "pidfile", HAS_ARG, QEMU_OPTION_pidfile }, +#ifdef TARGET_I386 + { "on-quit", HAS_ARG, QEMU_OPTION_on_quit }, +#endif /* temporary options */ { "pci", 0, QEMU_OPTION_pci }, @@ -3383,6 +3416,19 @@ case QEMU_OPTION_pidfile: create_pidfile(optarg); break; +#ifdef TARGET_I386 + case QEMU_OPTION_on_quit: + if(!strcmp(optarg, "ignore-unless-halted")) { + fprintf(stderr, "%s enabled\n", optarg); + on_quit = 1; + } + else if(!strcmp(optarg, "suspend-unless-halted")) { + fprintf(stderr, "%s enabled\n", optarg); + on_quit = 2; + } + else on_quit = 0; + break; +#endif #ifdef USE_KQEMU case QEMU_OPTION_no_kqemu: kqemu_allowed = 0; @@ -3696,6 +3742,23 @@ } } main_loop(); + +#ifdef TARGET_I386 + if( on_quit == 2 ) { + char *f = "suspended.qemu"; + if( ishalted() ) { + + fprintf(stderr, "VM is halted: removing suspend file %s\n",f); + unlink(f); + /* qemu_savevm(f); */ + } + else { + fprintf(stderr, "Autosaving VM to file %s\n",f); + qemu_savevm(f); + } + } +#endif + quit_timers(); return 0; }
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