From ffde22ac53b6d6b1d7206f1172176a667eead778 Mon Sep 17 00:00:00 2001 From: Ed Swierk Date: Thu, 15 Oct 2009 15:21:43 -0700 Subject: 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 Signed-off-by: Jan Kiszka Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- include/linux/kvm.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux/kvm.h') diff --git a/include/linux/kvm.h b/include/linux/kvm.h index f8f8900fc5ec..b694c1d2f918 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -436,6 +436,9 @@ struct kvm_ioeventfd { #endif #define KVM_CAP_IOEVENTFD 36 #define KVM_CAP_SET_IDENTITY_MAP_ADDR 37 +#ifdef __KVM_HAVE_XEN_HVM +#define KVM_CAP_XEN_HVM 38 +#endif #ifdef KVM_CAP_IRQ_ROUTING @@ -488,6 +491,18 @@ struct kvm_x86_mce { }; #endif +#ifdef KVM_CAP_XEN_HVM +struct kvm_xen_hvm_config { + __u32 flags; + __u32 msr; + __u64 blob_addr_32; + __u64 blob_addr_64; + __u8 blob_size_32; + __u8 blob_size_64; + __u8 pad2[30]; +}; +#endif + #define KVM_IRQFD_FLAG_DEASSIGN (1 << 0) struct kvm_irqfd { @@ -546,6 +561,7 @@ struct kvm_irqfd { #define KVM_CREATE_PIT2 _IOW(KVMIO, 0x77, struct kvm_pit_config) #define KVM_SET_BOOT_CPU_ID _IO(KVMIO, 0x78) #define KVM_IOEVENTFD _IOW(KVMIO, 0x79, struct kvm_ioeventfd) +#define KVM_XEN_HVM_CONFIG _IOW(KVMIO, 0x7a, struct kvm_xen_hvm_config) /* * ioctls for vcpu fds -- cgit v1.2.2