Re: [PATCH v4 2/9] KVM: x86: MMU: Clear CR3 LAM bits when allocate shadow root

["Yang, Weijiang" <weijiang.yang@xxxxxxxxx>]

On 2/9/2023 10:40 AM, Robert Hoo wrote:

[...]


> -
> +#ifdef CONFIG_X86_64
> +	root_pgd = mmu->get_guest_pgd(vcpu) & ~(X86_CR3_LAM_U48 | X86_CR3_LAM_U57);
> +#else
>   	root_pgd = mmu->get_guest_pgd(vcpu);
> +#endif

I prefer using:

root_pgd = mmu->get_guest_pgd(vcpu);

if (IS_ENABLED(CONFIG_X86_64))

    root_pgd &= ~(X86_CR3_LAM_U48 | X86_CR3_LAM_U57);

I looks more structured.


>   	root_gfn = root_pgd >> PAGE_SHIFT;
>   
>   	if (mmu_check_root(vcpu, root_gfn))