Re: [libvirt] PATCH: recent qemu-kvm requires -enable-kvm flag to activate VT optimization

Right - I left it out of the patch by mistake. New attachment has the needed test: + if (strstr(help, "-enable-kvm")) + flags |= QEMUD_CMD_FLAG_ENABLEKVM; -Steve Daniel Veillard wrote: > On Sun, Nov 15, 2009 at 07:03:51PM -0800, Steve Yarmie wrote: > >> Hello, >> >> Recent qemu releases require command option '-enable-qemu' in order >> for the kvm functionality be activated. Libvirt needs to pass this flag >> to qemu when starting a domain. Note that without the option, >> even if both the kernel and qemu support KVM, KVM will not be activated >> and VMs will be slow as molasses ;) >> >> I added a check in qemu_conf.c to see if `qemu -help` emits the -enable-kvm >> flag, and if so, use the flag accordingly. >> >> There exists a check in src/qemu/qemu_conf.c to check for the -no-kvm flag. >> This check works the same way. >> >> Adding the included code will not break systems where qemu does not >> have the option. >> >> See 'qemu -help': >> ... >> -enable-kvm enable KVM full virtualization support ... >> >> included patch against src/qemu/qemu_conf.{c,h} >> >> -Steve >> >> >> > > >> diff -ur libvirt/src/qemu/qemu_conf.c libvirt-qemu-enable-kvm/src/qemu/qemu_conf.c >> --- libvirt/src/qemu/qemu_conf.c 2009-11-08 20:57:08.438908134 -0800 >> +++ libvirt-qemu-enable-kvm/src/qemu/qemu_conf.c 2009-11-08 22:36:04.299921427 -0800 >> @@ -1602,6 +1602,7 @@ >> struct utsname ut; >> int disableKQEMU = 0; >> int disableKVM = 0; >> + int enableKVM = 0; >> int qargc = 0, qarga = 0; >> const char **qargv = NULL; >> int qenvc = 0, qenva = 0; >> @@ -1660,6 +1661,15 @@ >> def->virtType == VIR_DOMAIN_VIRT_QEMU) >> disableKVM = 1; >> >> + /* Should explicitly enable KVM if >> + * 1. Guest domain is 'qemu' >> + * 2. The qemu binary has the -enable-kvm flag >> + * NOTE: user must be responsible to load the kvm modules >> + */ >> + if ((qemuCmdFlags & QEMUD_CMD_FLAG_ENABLE_KVM) && >> + def->virtType == VIR_DOMAIN_VIRT_QEMU) >> + enableKVM = 1; >> + >> /* >> * Need to force a 32-bit guest CPU type if >> * >> @@ -1787,6 +1797,8 @@ >> ADD_ARG_LIT("-no-kqemu"); >> if (disableKVM) >> ADD_ARG_LIT("-no-kvm"); >> + if (enableKVM) >> + ADD_ARG_LIT("-enable-kvm"); >> ADD_ARG_LIT("-m"); >> ADD_ARG_LIT(memory); >> if (def->hugepage_backed) { >> diff -ur libvirt/src/qemu/qemu_conf.h libvirt-qemu-enable-kvm/src/qemu/qemu_conf.h >> --- libvirt/src/qemu/qemu_conf.h 2009-11-08 20:57:08.438908134 -0800 >> +++ libvirt-qemu-enable-kvm/src/qemu/qemu_conf.h 2009-11-08 14:57:39.000000000 -0800 >> @@ -73,6 +73,7 @@ >> QEMUD_CMD_FLAG_XEN_DOMID = (1 << 20), /* -xen-domid (new style xen integration) */ >> QEMUD_CMD_FLAG_MIGRATE_QEMU_UNIX = (1 << 21), /* Does qemu support unix domain sockets for migration? */ >> QEMUD_CMD_FLAG_CHARDEV = (1 << 22), /* Is the new -chardev arg available */ >> + QEMUD_CMD_FLAG_ENABLE_KVM = (1 << 23), /* Is the -enable-kvm flag available to "enable KVM full virtualization support" */ >> }; >> >> /* Main driver state */ >> > > Patch seems incomplete as I don't see any detection code setting up > QEMUD_CMD_FLAG_ENABLE_KVM in qemuCmdFlags > > Daniel > >