Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-16 Thread Ian Campbell
On Fri, 2015-04-03 at 14:39 +0200, Julien Grall wrote: On 02/04/2015 18:19, Ian Campbell wrote: On Thu, 2015-04-02 at 17:01 +0100, Ian Campbell wrote: On Thu, 2015-04-02 at 16:50 +0100, Ian Campbell wrote: Writing to the bottom half (e.g. w0) of a register implicitly clears the top

Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-06 Thread Julien Grall
On 02/04/2015 18:19, Ian Campbell wrote: On Thu, 2015-04-02 at 17:01 +0100, Ian Campbell wrote: On Thu, 2015-04-02 at 16:50 +0100, Ian Campbell wrote: Writing to the bottom half (e.g. w0) of a register implicitly clears the top half, IIRC, so I think a kernel is unlikely to want to do this,

Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-02 Thread Ian Campbell
On Thu, 2015-04-02 at 16:14 +0100, Julien Grall wrote: Hi Ian, On 31/03/2015 11:07, Ian Campbell wrote: Reduces the use of goto in the trap handlers to none. Some explcitily 32-bit types become register_t here, but that's OK, on s/explcitily/explicitly/ 32-bit they are 32-bit

Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-02 Thread Ian Campbell
On Thu, 2015-04-02 at 16:50 +0100, Ian Campbell wrote: Writing to the bottom half (e.g. w0) of a register implicitly clears the top half, IIRC, so I think a kernel is unlikely to want to do this, even if it could (which I'm not quite convinced of). That said, I'll see if I can make something

Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-02 Thread Julien Grall
Hi Ian, On 31/03/2015 11:07, Ian Campbell wrote: Reduces the use of goto in the trap handlers to none. Some explcitily 32-bit types become register_t here, but that's OK, on s/explcitily/explicitly/ 32-bit they are 32-bit already and on 64-bit it is fine/harmless to set the larger

Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-02 Thread Julien Grall
On 02/04/2015 16:31, Ian Campbell wrote: On Thu, 2015-04-02 at 16:14 +0100, Julien Grall wrote: Hi Ian, On 31/03/2015 11:07, Ian Campbell wrote: Reduces the use of goto in the trap handlers to none. Some explcitily 32-bit types become register_t here, but that's OK, on

Re: [Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-04-02 Thread Ian Campbell
On Thu, 2015-04-02 at 16:45 +0100, Julien Grall wrote: On 02/04/2015 16:31, Ian Campbell wrote: On Thu, 2015-04-02 at 16:14 +0100, Julien Grall wrote: Hi Ian, On 31/03/2015 11:07, Ian Campbell wrote: Reduces the use of goto in the trap handlers to none. Some explcitily 32-bit

[Xen-devel] [PATCH 04/19] xen: arm: provide and use a handle_raz_wi helper

2015-03-31 Thread Ian Campbell
Reduces the use of goto in the trap handlers to none. Some explcitily 32-bit types become register_t here, but that's OK, on 32-bit they are 32-bit already and on 64-bit it is fine/harmless to set the larger register, a 32-bit guest won't see the top half in any case. Unlike the previous code