linux-kernel - Re: [PATCH v2 06/27] drm/i915/gvt: Put the page reference obtained by KVM's gfn_to

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]

Date:   Fri, 17 Mar 2023 14:18:54 +0800
From:   Yan Zhao <yan.y.zhao@...el.com>
To:     Sean Christopherson <seanjc@...gle.com>
CC:     Paolo Bonzini <pbonzini@...hat.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Zhi Wang <zhi.a.wang@...el.com>, <kvm@...r.kernel.org>,
        <intel-gvt-dev@...ts.freedesktop.org>,
        <intel-gfx@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Ben Gardon <bgardon@...gle.com>
Subject: Re: [PATCH v2 06/27] drm/i915/gvt: Put the page reference obtained
 by KVM's gfn_to_pfn()

Reviewed-by: Yan Zhao <yan.y.zhao@...el.com>

On Fri, Mar 10, 2023 at 04:22:37PM -0800, Sean Christopherson wrote:
> Put the struct page reference acquired by gfn_to_pfn(), KVM's API is that
> the caller is ultimately responsible for dropping any reference.
> 
> Note, kvm_release_pfn_clean() ensures the pfn is actually a refcounted
> struct page before trying to put any references.
> 
> Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support")
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  drivers/gpu/drm/i915/gvt/gtt.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index d59c7ab9d224..15848b041a0d 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -1160,6 +1160,7 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu,
>  	unsigned long gfn = ops->get_pfn(entry);
>  	kvm_pfn_t pfn;
>  	int max_level;
> +	int ret;
>  
>  	if (!HAS_PAGE_SIZES(vgpu->gvt->gt->i915, I915_GTT_PAGE_SIZE_2M))
>  		return 0;
> @@ -1179,7 +1180,9 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu,
>  	if (!pfn_valid(pfn))
>  		return -EINVAL;
>  
> -	return PageTransHuge(pfn_to_page(pfn));
> +	ret = PageTransHuge(pfn_to_page(pfn));
> +	kvm_release_pfn_clean(pfn);
> +	return ret;
>  }
>  
>  static int split_2MB_gtt_entry(struct intel_vgpu *vgpu,
> -- 
> 2.40.0.rc1.284.g88254d51c5-goog
>