linux-kernel - Re: [PATCH v4 29/29] drm/i915/gvt: Drop final dependencies on KVM internal details

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Message-ID: <34e5cea4-b837-cb1e-15c1-fcbf2dba4f71@intel.com>
Date:   Tue, 1 Aug 2023 14:42:43 +0300
From:   "Wang, Zhi A" <zhi.a.wang@...el.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>
CC:     <kvm@...r.kernel.org>, <intel-gvt-dev@...ts.freedesktop.org>,
        <intel-gfx@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Yan Zhao <yan.y.zhao@...el.com>,
        Yongwei Ma <yongwei.ma@...el.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: Re: [PATCH v4 29/29] drm/i915/gvt: Drop final dependencies on KVM
 internal details

On 7/29/2023 4:35 AM, Sean Christopherson wrote:
> Open code gpa_to_gfn() in kvmgt_page_track_write() and drop KVMGT's
> dependency on kvm_host.h, i.e. include only kvm_page_track.h.  KVMGT
> assumes "gfn == gpa >> PAGE_SHIFT" all over the place, including a few
> lines below in the same function with the same gpa, i.e. there's no
> reason to use KVM's helper for this one case.
> 
> No functional change intended.
> 
> Reviewed-by: Yan Zhao <yan.y.zhao@...el.com>
> Tested-by: Yongwei Ma <yongwei.ma@...el.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>   drivers/gpu/drm/i915/gvt/gvt.h   | 3 ++-
>   drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +-
>   2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index 2d65800d8e93..53a0a42a50db 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -34,10 +34,11 @@
>   #define _GVT_H_
>   
>   #include <uapi/linux/pci_regs.h>
> -#include <linux/kvm_host.h>
>   #include <linux/vfio.h>
>   #include <linux/mdev.h>
>   
> +#include <asm/kvm_page_track.h>
> +
>   #include "i915_drv.h"
>   #include "intel_gvt.h"
>   
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index eb50997dd369..aaed3969f204 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1585,7 +1585,7 @@ static void kvmgt_page_track_write(gpa_t gpa, const u8 *val, int len,
>   
>   	mutex_lock(&info->vgpu_lock);
>   
> -	if (kvmgt_gfn_is_write_protected(info, gpa_to_gfn(gpa)))
> +	if (kvmgt_gfn_is_write_protected(info, gpa >> PAGE_SHIFT))
>   		intel_vgpu_page_track_handler(info, gpa,
>   						     (void *)val, len);
>   
Reviewed-by: Zhi Wang <zhi.a.wang@...el.com>