[PATCH 13/41] KVM: Allow userspace to process hypercalls which have no kernel handler

Avi Kivity
2007-04-01T14:35:10Z

This is useful for paravirtualized graphics devices, for example.

Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
---
drivers/kvm/kvm_main.c | 18 +++++++++++++++++-
include/linux/kvm.h | 10 +++++++++-
2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 39cf8fd..de93117 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1203,7 +1203,16 @@ int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run)
}
switch (nr) {
default:
- ;
+ run->hypercall.args[0] = a0;
+ run->hypercall.args[1] = a1;
+ run->hypercall.args[2] = a2;
+ run->hypercall.args[3] = a3;
+ run->hypercall.args[4] = a4;
+ run->hypercall.args[5] = a5;
+ run->hypercall.ret = ret;
+ run->hypercall.longmode = is_long_mode(vcpu);
+ kvm_arch_ops->decache_regs(vcpu);
+ return 0;
}
vcpu->regs[VCPU_REGS_RAX] = ret;
kvm_arch_ops->decache_regs(vcpu);
@@ -1599,6 +1608,13 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

vcpu->mmio_needed = 0;

+ if (kvm_run->exit_type == KVM_EXIT_TYPE_VM_EXIT
+ && kvm_run->exit_reason == KVM_EXIT_HYPERCALL) {
+ kvm_arch_ops->cache_regs(vcpu);
+ vcpu->regs[VCPU_REGS_RAX] = kvm_run->hypercall.ret;
+ kvm_arch_ops->decache_regs(vcpu);
+ }
+
r = kvm_arch_ops->run(vcpu, kvm_run);

vcpu_put(vcpu);
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index c93cf53..9151ebf 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -11,7 +11,7 @@
#include <asm/types.h>
#include <linux/ioctl.h>

-#define KVM_API_VERSION 6
+#define KVM_API_VERSION 7

/*
* Architectural interrupt line count, and the size of the bitmap needed
@@ -41,6 +41,7 @@ enum kvm_exit_reason {
KVM_EXIT_UNKNOWN = 0,
KVM_EXIT_EXCEPTION = 1,
KVM_EXIT_IO = 2,
+ KVM_EXIT_HYPERCALL = 3,
KVM_EXIT_DEBUG = 4,
KVM_EXIT_HLT = 5,
KVM_EXIT_MMIO = 6,
@@ -103,6 +104,13 @@ struct kvm_run {
__u32 len;
__u8 is_write;
} mmio;
+ /* KVM_EXIT_HYPERCALL */
+ struct {
+ __u64 args[6];
+ __u64 ret;
+ __u32 longmode;
+ __u32 pad;
+ } hypercall;
};
};