From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Egger, Christoph" Subject: Re: [PATCH 3/8] xen/arm: Implement p2m_type_t as an enum Date: Mon, 9 Dec 2013 12:16:24 +0100 Message-ID: <52A5A688.3040100@amazon.de> References: <1386258131-755-1-git-send-email-julien.grall@linaro.org> <1386258131-755-4-git-send-email-julien.grall@linaro.org> <52A0A0F2.8010408@amazon.de> <1386259001.20047.87.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VpypX-0007oL-7X for xen-devel@lists.xenproject.org; Mon, 09 Dec 2013 11:16:51 +0000 In-Reply-To: <1386259001.20047.87.camel@kazak.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, Julien Grall , stefano.stabellini@citrix.com, time@xen.org, patches@linaro.org List-Id: xen-devel@lists.xenproject.org On 05.12.13 16:56, Ian Campbell wrote: > On Thu, 2013-12-05 at 16:51 +0100, Egger, Christoph wrote: >> On 05.12.13 16:42, Julien Grall wrote: >>> Until now, Xen doesn't know the type of the page (ram, foreign page, mmio,...). >>> Introduce p2m_type_t with basic types: >>> - p2m_invalid: Nothing is mapped here >>> - p2m_ram_rw: Normal read/write guest RAM >>> - p2m_ram_ro: Read-only guest RAM >>> - p2m_mmio_direct: Read/write mapping of device memory >>> - p2m_map_foreign: RAM page from foreign guest >>> >>> Signed-off-by: Julien Grall >>> --- >>> xen/include/asm-arm/p2m.h | 13 ++++++++++--- >>> 1 file changed, 10 insertions(+), 3 deletions(-) >>> >>> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h >>> index f079f00..b24f94a 100644 >>> --- a/xen/include/asm-arm/p2m.h >>> +++ b/xen/include/asm-arm/p2m.h >>> @@ -20,6 +20,16 @@ struct p2m_domain { >>> uint8_t vmid; >>> }; >>> >>> +typedef enum { >>> + p2m_invalid = 0, /* Nothing mapped here */ >>> + p2m_ram_rw = 1, /* Normal read/write guest RAM */ >>> + p2m_ram_ro = 2, /* Read-only; writes are silently dropped */ >>> + p2m_mmio_direct = 3, /* Read/write mapping of genuine MMIO area */ >>> + p2m_map_foreign = 4, /* Ram pages from foreign domain */ >>> +} p2m_type_t; >>> + >>> +#define p2m_is_foreign(_t) ((_t) == p2m_map_foreign) >>> + >> >> Is it possible to merge p2m_type_t with x86 and move into common code? > > Not really, the p2m handling is very different on the two arches, even > if they look superficially similar at this level. That does not imply there is no common logic from the algorithm POV. Do you see a way split the algorithm into architecture-specific and architecture-independent parts? > x86 has more types than can fit in the available pte space on ARM for a > start. > > I'd like to keep them separate please. Ok. Then leave the declaration in the architecture specific part and make the accessors available for the common code. In OO-languages this is called an 'interface'. Christoph