linux-kernel - Re: [PATCH 10/12] KVM: cleanup and add shortcuts to kvm_range_has_memory

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Message-ID: <20240717222348.pau4yzeq6q5kkk2p@amd.com>
Date: Wed, 17 Jul 2024 17:23:48 -0500
From: Michael Roth <michael.roth@....com>
To: Paolo Bonzini <pbonzini@...hat.com>
CC: <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>, <seanjc@...gle.com>
Subject: Re: [PATCH 10/12] KVM: cleanup and add shortcuts to
 kvm_range_has_memory_attributes()

On Thu, Jul 11, 2024 at 06:27:53PM -0400, Paolo Bonzini wrote:
> Use a guard to simplify early returns, and add two more easy
> shortcuts.  If the requested attributes are invalid, the attributes
> xarray will never show them as set.  And if testing a single page,
> kvm_get_memory_attributes() is more efficient.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---
>  virt/kvm/kvm_main.c | 42 ++++++++++++++++++++----------------------
>  1 file changed, 20 insertions(+), 22 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index f817ec66c85f..8ab9d8ff7b74 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2392,6 +2392,14 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
>  #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
>  
>  #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
> +static u64 kvm_supported_mem_attributes(struct kvm *kvm)
> +{
> +	if (!kvm || kvm_arch_has_private_mem(kvm))
> +		return KVM_MEMORY_ATTRIBUTE_PRIVATE;
> +
> +	return 0;
> +}
> +
>  /*
>   * Returns true if _all_ gfns in the range [@start, @end) have attributes
>   * matching @attrs.
> @@ -2400,40 +2408,30 @@ bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
>  				     unsigned long attrs)
>  {
>  	XA_STATE(xas, &kvm->mem_attr_array, start);
> +	unsigned long mask = kvm_supported_mem_attributes(kvm);;

Extra semicolon.

Otherwise:

Reviewed-by: Michael Roth <michael.roth@....com>