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SubjectRe: [PATCH 7/9] KVM, VMX: add support for switching of PERF_GLOBAL_CTRL
On 10/03/2011 03:49 PM, Gleb Natapov wrote:
> Some cpus have special support for switching PERF_GLOBAL_CTRL msr.
> Add logic to detect if such support exists and works properly and extend
> msr switching code to use it if available. Also extend number of generic
> msr switching entries to 8.
>
>
> static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);
> static DEFINE_SPINLOCK(vmx_vpid_lock);
> @@ -1195,10 +1196,29 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
> {
> unsigned i;
> struct msr_autoload *m =&vmx->msr_autoload;
> + u32 entry_load, exit_load;
> + bool done = false;
>
> - if (msr == MSR_EFER&& cpu_has_load_ia32_efer) {
> - vmcs_clear_bits(VM_ENTRY_CONTROLS, VM_ENTRY_LOAD_IA32_EFER);
> - vmcs_clear_bits(VM_EXIT_CONTROLS, VM_EXIT_LOAD_IA32_EFER);
> + switch (msr) {
> + case MSR_EFER:
> + if (cpu_has_load_ia32_efer) {
> + entry_load = VM_ENTRY_LOAD_IA32_EFER;
> + exit_load = VM_EXIT_LOAD_IA32_EFER;
> + done = true;
> + }
> + break;
> + case MSR_CORE_PERF_GLOBAL_CTRL:
> + if (cpu_has_load_perf_global_ctrl) {
> + entry_load = VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
> + exit_load = VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
> + done = true;
> + }
> + break;
> + }
> +
> + if (done) {
> + vmcs_clear_bits(VM_ENTRY_CONTROLS, entry_load);
> + vmcs_clear_bits(VM_EXIT_CONTROLS, exit_load);
> return;
> }
>
>

This is ugly. How about

if (msr == MSR_EFER && cpu_has_load_ia32_efer) {
clear_atomic_switch_msr_special(VM_ENTRY_LOAD_IA32_EFER,
VM_EXIT_LOAD_IA32_EFER);
return;
}
avoids the fake 'done' variable.

--
error compiling committee.c: too many arguments to function



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