Re: [PATCH v3 3/7] x86/xen: drop tests for highmem in pv code

From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Juergen Gross <jgross@suse.com>,
	xen-devel@lists.xenproject.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 3/7] x86/xen: drop tests for highmem in pv code
Date: Sat, 8 Aug 2020 22:22:07 -0400	[thread overview]
Message-ID: <60f40558-a3a8-2c1e-2c32-09f93bfca724@oracle.com> (raw)
In-Reply-To: <20200807083826.16794-4-jgross@suse.com>

On 8/7/20 4:38 AM, Juergen Gross wrote:
> With support for 32-bit pv guests gone pure pv-code no longer needs to
> test for highmem. Dropping those tests removes the need for flushing
> in some places.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

with a suggestion

> ---
>  arch/x86/xen/enlighten_pv.c |  11 ++-
>  arch/x86/xen/mmu_pv.c       | 138 ++++++++++++++----------------------
>  2 files changed, 57 insertions(+), 92 deletions(-)
>
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index 7d90b3da8bb4..9fec952f84f3 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -347,6 +347,7 @@ static void set_aliased_prot(void *v, pgprot_t prot)
>  	unsigned long pfn;
>  	struct page *page;
>  	unsigned char dummy;
> +	void *av;

to rename this to va since you are modifying those lines anyway.

>  
>  	ptep = lookup_address((unsigned long)v, &level);
>  	BUG_ON(ptep == NULL);
> @@ -383,14 +384,10 @@ static void set_aliased_prot(void *v, pgprot_t prot)
>  	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
>  		BUG();
>  
> -	if (!PageHighMem(page)) {
> -		void *av = __va(PFN_PHYS(pfn));
> +	av = __va(PFN_PHYS(pfn));
>  