On 02/09/2011 07:29 PM, Joerg Roedel wrote:
This patch implements two new vm-ioctls to get and set the
virtual_tsc_khz if the machine supports tsc-scaling. Setting
the tsc-frequency is only possible before userspace creates
any vcpu.
Signed-off-by: Joerg Roedel<joerg.roedel@xxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm.c | 3 +++
arch/x86/kvm/x86.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/kvm.h | 4 ++++
4 files changed, 46 insertions(+), 0 deletions(-)
Documentation/kvm/api.txt +++++++++++++
@@ -633,6 +633,7 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn);
extern bool tdp_enabled;
+extern int kvm_has_tsc_control;
bool
+ case KVM_SET_TSC_KHZ: {
+ u32 user_tsc_khz;
+
+ if (!kvm_has_tsc_control)
+ break;
+
+ /*
+ * We force the tsc frequency to be set before any
+ * vcpu is created
+ */
+ if (atomic_read(&kvm->online_vcpus)> 0)
+ goto out;
What if a vcpu is created here? No locking AFAICS.
+
+ user_tsc_khz = arg;
+
+ kvm_arch_set_tsc_khz(kvm, user_tsc_khz);
+
Error check for impossible values (0, values the tsc multiplier can't
reach)?
+ r = 0;
+ goto out;
+ }
+ case KVM_GET_TSC_KHZ: {
+
+ if (!kvm_has_tsc_control)
+ break;
+
+ r = -EFAULT;
+ if (copy_to_user(argp,&kvm->arch.virtual_tsc_khz, sizeof(__u32)))
+ goto out;
Should be the return value, no?
+
+ r = 0;
+ goto out;
+ }
default:
;
@@ -677,6 +678,9 @@ struct kvm_clock_data {
#define KVM_SET_PIT2 _IOW(KVMIO, 0xa0, struct kvm_pit_state2)
/* Available with KVM_CAP_PPC_GET_PVINFO */
#define KVM_PPC_GET_PVINFO _IOW(KVMIO, 0xa1, struct kvm_ppc_pvinfo)
+/* Available with KVM_CAP_TSC_CONTROL */
+#define KVM_SET_TSC_KHZ _IOW(KVMIO, 0xa2, __u32)
+#define KVM_GET_TSC_KHZ _IOR(KVMIO, 0xa3, __u32)
_IO() - use arg or return value
_IOW/_IOR - copy_to/from_user()
pick one, but don't mix.
--
error compiling committee.c: too many arguments to function
--
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