Re: [PATCH v3 09/10] x86/resctrl: Add arch_has_{sparse,empty}_bitmaps to explain CAT differences

From: Reinette Chatre <reinette.chatre@intel.com>
To: James Morse <james.morse@arm.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	H Peter Anvin <hpa@zytor.com>, Babu Moger <Babu.Moger@amd.com>
Subject: Re: [PATCH v3 09/10] x86/resctrl: Add arch_has_{sparse,empty}_bitmaps to explain CAT differences
Date: Tue, 19 May 2020 11:55:02 -0700	[thread overview]
Message-ID: <2f8d9fb3-da66-21ff-147b-d1f7deaaed73@intel.com> (raw)
In-Reply-To: <20200518131924.7741-10-james.morse@arm.com>

Hi James,

Thank you very much for adding the handling of empty bitmaps. This looks
good to me, just one comment ...

On 5/18/2020 6:19 AM, James Morse wrote:
> -bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
> +static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
>  {
>  	unsigned long first_bit, zero_bit, val;
>  	unsigned int cbm_len = r->cache.cbm_len;
> @@ -93,7 +95,8 @@ bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
>  		return false;
>  	}
>  
> -	if (val == 0 || val > r->default_ctrl) {
> +	if ((!r->cache.arch_has_empty_bitmaps && val == 0) ||
> +	    (val > r->default_ctrl)) {
>  		rdt_last_cmd_puts("Mask out of range\n");
>  		return false;

There is unnecessary parentheses around 'val > r->default_ctrl'

Reinette