From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Wed, 09 Mar 2022 06:18:40 +0000 Subject: Re: [PATCH 11/12] swiotlb: merge swiotlb-xen initialization into swiotlb Message-Id: <20220309061840.GA31435@lst.de> List-Id: References: <20220301105311.885699-1-hch@lst.de> <20220301105311.885699-12-hch@lst.de> <6a22ea1e-4823-5c3b-97ee-a29155404a0d@oracle.com> In-Reply-To: <6a22ea1e-4823-5c3b-97ee-a29155404a0d@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Boris Ostrovsky Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, x86@kernel.org, Anshuman Khandual , Tom Lendacky , Konrad Rzeszutek Wilk , Stefano Stabellini , Juergen Gross , Joerg Roedel , David Woodhouse , Lu Baolu , Robin Murphy , linux-arm-kernel@lists.infradead.org, xen-devel@lists.xenproject.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-hyperv@vger.kernel.org, tboot-devel@lists.sourceforge.net, linux-pci@vger.kernel.org On Tue, Mar 08, 2022 at 04:38:21PM -0500, Boris Ostrovsky wrote: > > On 3/1/22 5:53 AM, Christoph Hellwig wrote: >> Allow to pass a remap argument to the swiotlb initialization functions >> to handle the Xen/x86 remap case. ARM/ARM64 never did any remapping >> from xen_swiotlb_fixup, so we don't even need that quirk. > > > Any chance this patch could be split? Lots of things are happening here and it's somewhat hard to review. (Patch 7 too BTW but I think I managed to get through it) What would be your preferred split? >> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c >> index e0def4b1c3181..2f2c468acb955 100644 >> --- a/arch/x86/kernel/pci-dma.c >> +++ b/arch/x86/kernel/pci-dma.c >> @@ -71,15 +71,12 @@ static inline void __init pci_swiotlb_detect(void) >> #endif /* CONFIG_SWIOTLB */ >> #ifdef CONFIG_SWIOTLB_XEN >> -static bool xen_swiotlb; >> - >> static void __init pci_xen_swiotlb_init(void) >> { >> if (!xen_initial_domain() && !x86_swiotlb_enable) >> return; > > > Now that there is a single call site for this routine I think this check can be dropped. We are only called here for xen_initial_domain()=true. The callsite just checks xen_pv_domain() and itself is called unconditionally during initialization.