----- Original Message -----
> From: "Gustavo A. R. Silva" <garsilva@xxxxxxxxxxxxxx>
> To: "Paolo Bonzini" <pbonzini@xxxxxxxxxx>, "Radim Krčmář" <rkrcmar@xxxxxxxxxx>, "Thomas Gleixner"
> <tglx@xxxxxxxxxxxxx>, "Ingo Molnar" <mingo@xxxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>, x86@xxxxxxxxxx
> Cc: kvm@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, "Gustavo A. R. Silva" <garsilva@xxxxxxxxxxxxxx>
> 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).
Paolo
>
> Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
> ---
> 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
>
>
