linux-kernel - Re: [PATCH 13/18] KVM: x86/mmu: Avoid warning when installing non-private memory attributes

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: <ZuSOyipSCOi_gDyM@google.com>
Date: Fri, 13 Sep 2024 12:13:14 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Nicolas Saenz Julienne <nsaenz@...zon.com>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org, pbonzini@...hat.com, 
	vkuznets@...hat.com, linux-doc@...r.kernel.org, linux-hyperv@...r.kernel.org, 
	linux-arch@...r.kernel.org, linux-trace-kernel@...r.kernel.org, 
	graf@...zon.de, dwmw2@...radead.org, paul@...zon.com, mlevitsk@...hat.com, 
	jgowans@...zon.com, corbet@....net, decui@...rosoft.com, tglx@...utronix.de, 
	mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org, 
	amoorthy@...gle.com
Subject: Re: [PATCH 13/18] KVM: x86/mmu: Avoid warning when installing
 non-private memory attributes

On Sun, Jun 09, 2024, Nicolas Saenz Julienne wrote:
> In preparation to introducing RWX memory attributes, make sure
> user-space is attempting to install a memory attribute with
> KVM_MEMORY_ATTRIBUTE_PRIVATE before throwing a warning on systems with
> no private memory support.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenz@...zon.com>
> ---
>  arch/x86/kvm/mmu/mmu.c | 8 ++++++--
>  virt/kvm/kvm_main.c    | 1 +
>  2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index b0c210b96419f..d56c04fbdc66b 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -7359,6 +7359,9 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
>  bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
>  					struct kvm_gfn_range *range)
>  {
> +	unsigned long attrs = range->arg.attributes;
> +	bool priv_attr = attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE;

It's probably worth making this check generic straightaway, e.g. build and then
check the set of allowed attributes, similar to how check_memory_region_flags()
builds and checks the set of allowed flags.