From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Tue, 12 Apr 2011 21:47:14 +0100 Subject: A15 h/w virtulization support In-Reply-To: References: Message-ID: <20110412204714.GD7806@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 12, 2011 at 12:16:10PM +0530, Subash Patel wrote: > If I am not wrong, Cortex-A15 is WIP with many SoC vendors. From my > understanding, A15 has additional operational mode "hypervisor mode" > and SMMU support for GuestOS memory to IPA in VMM, and IPA in VMM into > PA. I was curious to know whether ARM v7 changes for Linux > is happening for this? This will help to understand the KVM changes > that may be required to run Linux directly in ring-0, and support > guest OS? Currently, I am planning no work on merging virtualization support. Linus complained during the last merge window about the size of the arch/arm sub-tree, and we - as the *entire* ARM community - really need to address this issue right now. Therefore, I will be taking no patches which aren't bug fixes or consolidation patches for code which already lives in the kernel. I am presently not convinced that many people are taking this issue seriously enough, believing that "someone else will sort it out for me." This isn't going to happen. If that's what many people are doing, then I believe that we'll see ARM being removed from mainline kernels. Longer term, folk need to open their minds and look through code which is already present to see whether code which one SoC already implements can be re-used for their SoC, and actually sort out re-using that code rather than submitting their own thing. I believe that we are far too large in mainline to allow anything new in. If you're wondering "why doesn't X do that work" the answer is that there have already been efforts to consolidate things, but because of the sheer amount of new ARM specific code flowing into the kernel, these consolidations completely disappear into the noise. We need an army of people working on this. So, at the moment, virtualization support for ARM in mainline kernels is completely out of the question.