linux-kernel - Re: [PATCH v7 04/10] iommu/amd: Introduce struct ivhd_dte

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Message-ID: <20241031124024.GE10193@nvidia.com>
Date: Thu, 31 Oct 2024 09:40:24 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Cc: linux-kernel@...r.kernel.org, iommu@...ts.linux.dev, joro@...tes.org,
	robin.murphy@....com, vasant.hegde@....com, kevin.tian@...el.com,
	jon.grimm@....com, santosh.shukla@....com, pandoh@...gle.com,
	kumaranand@...gle.com
Subject: Re: [PATCH v7 04/10] iommu/amd: Introduce struct ivhd_dte_flags to
 store persistent DTE flags

On Thu, Oct 31, 2024 at 09:16:18AM +0000, Suravee Suthikulpanit wrote:
> During early initialization, the driver parses IVRS IVHD block to get list
> of downstream devices along with their DTE flags (i.e INITPass, EIntPass,
> NMIPass, SysMgt, Lint0Pass, Lint1Pass). This information is currently
> store in the device DTE, and needs to be preserved when clearing
> and configuring each DTE, which makes it difficult to manage.
> 
> Introduce struct ivhd_dte_flags to store IVHD DTE settings for a device or
> range of devices, which are stored in the amd_ivhd_dev_flags_list during
> initial IVHD parsing.
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> ---
>  drivers/iommu/amd/amd_iommu_types.h |  15 ++++
>  drivers/iommu/amd/init.c            | 110 ++++++++++++++++++++--------
>  2 files changed, 96 insertions(+), 29 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

>  /* sets a specific bit in the device table entry. */
> +static void set_dte_bit(struct dev_table_entry *dte, u8 bit)
> +{
> +	int i = (bit >> 6) & 0x03;
> +	int _bit = bit & 0x3f;
> +
> +	dte->data[i] |= (1UL << _bit);
> +}

It would be nice to see the remaining DEV_ENTRY constants harmonized
with the DTE_ constants so there aren't two schemes for working with
the struct dev_table_entry, but that is an idea for some other series

Jason