linux-kernel - Re: [RFC 17/33] KVM: x86/mmu: Allow setting memory attributes if VSM enabled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <31cd6a37f565e07f3890027b3b3305a225f84956.camel@redhat.com>
Date:   Tue, 28 Nov 2023 09:39:49 +0200
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Nicolas Saenz Julienne <nsaenz@...zon.com>, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-hyperv@...r.kernel.org,
        pbonzini@...hat.com, seanjc@...gle.com, vkuznets@...hat.com,
        anelkz@...zon.com, graf@...zon.com, dwmw@...zon.co.uk,
        jgowans@...zon.com, corbert@....net, kys@...rosoft.com,
        haiyangz@...rosoft.com, decui@...rosoft.com, x86@...nel.org,
        linux-doc@...r.kernel.org
Subject: Re: [RFC 17/33] KVM: x86/mmu: Allow setting memory attributes if
 VSM enabled

On Wed, 2023-11-08 at 11:17 +0000, Nicolas Saenz Julienne wrote:
> VSM is also a user of memory attributes, so let it use
> kvm_set_mem_attributes().
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenz@...zon.com>
> ---
>  arch/x86/kvm/mmu/mmu.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index feca077c0210..a1fbb905258b 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -7265,7 +7265,8 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
>  	 * Zapping SPTEs in this case ensures KVM will reassess whether or not
>  	 * a hugepage can be used for affected ranges.
>  	 */
> -	if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm)))
> +	if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm) &&
> +			 !kvm_hv_vsm_enabled(kvm)))
>  		return false;

IMHO on the long term, memory attributes should either be always enabled,
or the above check should became more generic.

But otherwise this patch looks reasonable.

>  
>  	return kvm_unmap_gfn_range(kvm, range);
> @@ -7322,7 +7323,8 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
>  	 * a range that has PRIVATE GFNs, and conversely converting a range to
>  	 * SHARED may now allow hugepages.
>  	 */
> -	if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm)))
> +	if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm) &&
> +			 !kvm_hv_vsm_enabled(kvm)))
>  		return false;
>  
>  	/*

Best regards,
	Maxim Levitsky