Re: [Xen-devel] [PATCH v2 08/12] livepatch: Add support for inline asm hotpatching expectations

From: Konrad Rzeszutek Wilk <konrad@darnok.org>
To: Pawel Wieczorkiewicz <wipawel@amazon.de>
Cc: Tim Deegan <tim@xen.org>,
	wipawel@amazon.com, Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wl@xen.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	mpohlack@amazon.com, xen-devel@lists.xen.org,
	Ross Lagerwall <ross.lagerwall@citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	Jan Beulich <jbeulich@suse.com>,
	xen-devel@lists.xenproject.org
Subject: Re: [Xen-devel] [PATCH v2 08/12] livepatch: Add support for inline asm hotpatching expectations
Date: Thu, 5 Sep 2019 14:05:53 -0400	[thread overview]
Message-ID: <20190905180553.GA21466@localhost-live.lan> (raw)
In-Reply-To: <20190827084624.116917-9-wipawel@amazon.de>

> diff --git a/docs/misc/livepatch.pandoc b/docs/misc/livepatch.pandoc
> index 6ab7f4c2d2..92a424e918 100644
> --- a/docs/misc/livepatch.pandoc
> +++ b/docs/misc/livepatch.pandoc
> @@ -300,6 +300,7 @@ which describe the functions to be patched:
>          /* Added to livepatch payload version 2: */
>          uint8_t applied;
>          uint8_t _pad[7];
> +        livepatch_expectation_t expect;
>      };
>  
>  The size of the structure is 64 bytes on 64-bit hypervisors. It will be
                                ^^
I also updated this to be 104 and 92 (for 32-bit).

And added:
> @@ -336,6 +337,26 @@ The version 2 of the payload adds the following fields to the structure:
>    * `applied` tracks function's applied/reverted state. It has a boolean type
>      either LIVEPATCH_FUNC_NOT_APPLIED or LIVEPATCH_FUNC_APPLIED.
>    * `_pad[7]` adds padding to align to 8 bytes.
> +  * `expect` is an optional structure containing expected to-be-replaced data
> +    (mostly for inline asm patching). The `expect` structure format is:
> +
> +    struct livepatch_expectation {
> +        uint8_t enabled : 1;
> +        uint8_t len : 5;

uint8_t rsv : 2;

To make it clear what the extra two bits in the bit-field should have.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel