Hi Paolo,
Quoting Paolo Bonzini <[email protected]>:
> ----- Original Message -----
>> From: "Gustavo A. R. Silva" <[email protected]>
>> To: "Paolo Bonzini" <[email protected]>, "Radim Krčmář"
>> <[email protected]>, "Thomas Gleixner"
>> <[email protected]>, "Ingo Molnar" <[email protected]>, "H. Peter
>> Anvin" <[email protected]>, [email protected]
>> Cc: [email protected], [email protected], "Gustavo A.
>> R. Silva" <[email protected]>
>> Sent: Friday, November 3, 2017 11:58:19 PM
>> Subject: [PATCH] KVM: VMX: replace move_msr_up with swap macro
>>
>> Function move_msr_up is used to _manually_ swap MSR entries in MSR array.
>> This function can be removed and replaced using the swap macro instead.
>>
>> This code was detected with the help of Coccinelle.
>
> I think move_msr_up should instead change into a function like
>
> void mark_msr_for_save(struct vcpu_vmx *vmx, int index)
> {
> swap(vmx->guest_msrs[index], vmx->guest_msrs[vmx->save_nmsrs]);
> vmx->save_nmsrs++;
> }
>
> Using swap is useful, but it is also hiding what's going on exactly
> (in addition, using ++ inside a macro argument might be calling for
> trouble).
>
Thanks for your comments.
I'll work on v2 based on your feedback.
--
Gustavo A. R. Silva
> Paolo
>
>>
>> Signed-off-by: Gustavo A. R. Silva <[email protected]>
>> ---
>> The new lines are over 80 characters, but I think in this case that is
>> preferable over splitting them.
>>
>> arch/x86/kvm/vmx.c | 24 ++++++------------------
>> 1 file changed, 6 insertions(+), 18 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index e6c8ffa..210e491 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -2544,18 +2544,6 @@ static bool vmx_invpcid_supported(void)
>> return cpu_has_vmx_invpcid() && enable_ept;
>> }
>>
>> -/*
>> - * Swap MSR entry in host/guest MSR entry array.
>> - */
>> -static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
>> -{
>> - struct shared_msr_entry tmp;
>> -
>> - tmp = vmx->guest_msrs[to];
>> - vmx->guest_msrs[to] = vmx->guest_msrs[from];
>> - vmx->guest_msrs[from] = tmp;
>> -}
>> -
>> static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu)
>> {
>> unsigned long *msr_bitmap;
>> @@ -2600,28 +2588,28 @@ static void setup_msrs(struct vcpu_vmx *vmx)
>> if (is_long_mode(&vmx->vcpu)) {
>> index = __find_msr_index(vmx, MSR_SYSCALL_MASK);
>> if (index >= 0)
>> - move_msr_up(vmx, index, save_nmsrs++);
>> + swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
>> index = __find_msr_index(vmx, MSR_LSTAR);
>> if (index >= 0)
>> - move_msr_up(vmx, index, save_nmsrs++);
>> + swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
>> index = __find_msr_index(vmx, MSR_CSTAR);
>> if (index >= 0)
>> - move_msr_up(vmx, index, save_nmsrs++);
>> + swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
>> index = __find_msr_index(vmx, MSR_TSC_AUX);
>> if (index >= 0 && guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
>> - move_msr_up(vmx, index, save_nmsrs++);
>> + swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
>> /*
>> * MSR_STAR is only needed on long mode guests, and only
>> * if efer.sce is enabled.
>> */
>> index = __find_msr_index(vmx, MSR_STAR);
>> if ((index >= 0) && (vmx->vcpu.arch.efer & EFER_SCE))
>> - move_msr_up(vmx, index, save_nmsrs++);
>> + swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
>> }
>> #endif
>> index = __find_msr_index(vmx, MSR_EFER);
>> if (index >= 0 && update_transition_efer(vmx, index))
>> - move_msr_up(vmx, index, save_nmsrs++);
>> + swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
>>
>> vmx->save_nmsrs = save_nmsrs;
>
>
>>
>> --
>> 2.7.4
>>
>>
From 1583157448956642893@xxx Sat Nov 04 17:29:57 +0000 2017
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