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authorEd Swierk <eswierk@aristanetworks.com>2009-10-16 02:21:43 +0400
committerAvi Kivity <avi@redhat.com>2009-12-03 10:32:18 +0300
commitffde22ac53b6d6b1d7206f1172176a667eead778 (patch)
tree16ab77d364ba26928136e6d18463845941b6dd2c /arch/x86/include/asm/kvm.h
parent94c30d9ca6fd00a69e367b91b6e13572c41938c5 (diff)
downloadlinux-ffde22ac53b6d6b1d7206f1172176a667eead778.tar.xz
KVM: Xen PV-on-HVM guest support
Support for Xen PV-on-HVM guests can be implemented almost entirely in userspace, except for handling one annoying MSR that maps a Xen hypercall blob into guest address space. A generic mechanism to delegate MSR writes to userspace seems overkill and risks encouraging similar MSR abuse in the future. Thus this patch adds special support for the Xen HVM MSR. I implemented a new ioctl, KVM_XEN_HVM_CONFIG, that lets userspace tell KVM which MSR the guest will write to, as well as the starting address and size of the hypercall blobs (one each for 32-bit and 64-bit) that userspace has loaded from files. When the guest writes to the MSR, KVM copies one page of the blob from userspace to the guest. I've tested this patch with a hacked-up version of Gerd's userspace code, booting a number of guests (CentOS 5.3 i386 and x86_64, and FreeBSD 8.0-RC1 amd64) and exercising PV network and block devices. [jan: fix i386 build warning] [avi: future proof abi with a flags field] Signed-off-by: Ed Swierk <eswierk@aristanetworks.com> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/kvm.h')
-rw-r--r--arch/x86/include/asm/kvm.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index f02e87a5206f..ef9b4b73cce4 100644
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -19,6 +19,7 @@
#define __KVM_HAVE_MSIX
#define __KVM_HAVE_MCE
#define __KVM_HAVE_PIT_STATE2
+#define __KVM_HAVE_XEN_HVM
/* Architectural interrupt line count. */
#define KVM_NR_INTERRUPTS 256