From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Subject: Re: [PATCH 2/9] PCI/MSI: Support allocating virtual MSI interrupts Date: Fri, 1 Feb 2019 13:23:23 -0600 Message-ID: <20190201192323.GS229773@google.com> References: <20190131185656.17972-1-logang@deltatee.com> <20190131185656.17972-3-logang@deltatee.com> <20190131223932.GR229773@google.com> <74993e67-cdc5-234a-d26c-5c0177a0299a@deltatee.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <74993e67-cdc5-234a-d26c-5c0177a0299a@deltatee.com> Sender: linux-kernel-owner@vger.kernel.org To: Logan Gunthorpe , g@google.com Cc: linux-kernel@vger.kernel.org, linux-ntb@googlegroups.com, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kselftest@vger.kernel.org, Jon Mason , Joerg Roedel , Allen Hubbe , Dave Jiang , Serge Semin , Eric Pilmore , Thomas Gleixner , Marc Zyngier List-Id: iommu@lists.linux-foundation.org On Thu, Jan 31, 2019 at 03:52:09PM -0700, Logan Gunthorpe wrote: > On 2019-01-31 3:39 p.m., Bjorn Helgaas wrote: > >> diff --git a/include/linux/msi.h b/include/linux/msi.h > >> index 784fb52b9900..6458ab049852 100644 > >> --- a/include/linux/msi.h > >> +++ b/include/linux/msi.h > >> @@ -88,6 +88,7 @@ struct msi_desc { > >> __u8 multi_cap : 3; > >> __u8 maskbit : 1; > >> __u8 is_64 : 1; > >> + __u8 is_virtual : 1; > > > > You did the right thing by using the same style as what's already > > here, but does anybody know why are we using __u8 and __u16 here? > > > > Those typedefs are in include/uapi/asm-generic/int-l64.h, which > > suggests they're for things exported to user space, but I don't think > > that's the case here, so I'm wondering if we could someday replace > > these with u8 and u16. Obviously that wouldn't be part of *this* > > series. > > Yes, I was also confused by this. But I always follow the "when-in-rome" > rule. Thanks for following the "when-in-rome" rule. That seems so obvious that it wouldn't even need to be written down, but it is often ignored. > My understanding is the same as yours is that __u8 should be used > for userspace compatibility which doesn't apply here. If there is > consensus on this being wrong, I'd be happy to write a cleanup patch > that fixes it separate from this series. That'd be awesome. There are also a couple more in pci-driver.c that could be fixed at the same time. Bjorn From mboxrd@z Thu Jan 1 00:00:00 1970 From: helgaas at kernel.org (Bjorn Helgaas) Date: Fri, 1 Feb 2019 13:23:23 -0600 Subject: [PATCH 2/9] PCI/MSI: Support allocating virtual MSI interrupts In-Reply-To: <74993e67-cdc5-234a-d26c-5c0177a0299a@deltatee.com> References: <20190131185656.17972-1-logang@deltatee.com> <20190131185656.17972-3-logang@deltatee.com> <20190131223932.GR229773@google.com> <74993e67-cdc5-234a-d26c-5c0177a0299a@deltatee.com> Message-ID: <20190201192323.GS229773@google.com> On Thu, Jan 31, 2019 at 03:52:09PM -0700, Logan Gunthorpe wrote: > On 2019-01-31 3:39 p.m., Bjorn Helgaas wrote: > >> diff --git a/include/linux/msi.h b/include/linux/msi.h > >> index 784fb52b9900..6458ab049852 100644 > >> --- a/include/linux/msi.h > >> +++ b/include/linux/msi.h > >> @@ -88,6 +88,7 @@ struct msi_desc { > >> __u8 multi_cap : 3; > >> __u8 maskbit : 1; > >> __u8 is_64 : 1; > >> + __u8 is_virtual : 1; > > > > You did the right thing by using the same style as what's already > > here, but does anybody know why are we using __u8 and __u16 here? > > > > Those typedefs are in include/uapi/asm-generic/int-l64.h, which > > suggests they're for things exported to user space, but I don't think > > that's the case here, so I'm wondering if we could someday replace > > these with u8 and u16. Obviously that wouldn't be part of *this* > > series. > > Yes, I was also confused by this. But I always follow the "when-in-rome" > rule. Thanks for following the "when-in-rome" rule. That seems so obvious that it wouldn't even need to be written down, but it is often ignored. > My understanding is the same as yours is that __u8 should be used > for userspace compatibility which doesn't apply here. If there is > consensus on this being wrong, I'd be happy to write a cleanup patch > that fixes it separate from this series. That'd be awesome. There are also a couple more in pci-driver.c that could be fixed at the same time. Bjorn From mboxrd@z Thu Jan 1 00:00:00 1970 From: helgaas@kernel.org (Bjorn Helgaas) Date: Fri, 1 Feb 2019 13:23:23 -0600 Subject: [PATCH 2/9] PCI/MSI: Support allocating virtual MSI interrupts In-Reply-To: <74993e67-cdc5-234a-d26c-5c0177a0299a@deltatee.com> References: <20190131185656.17972-1-logang@deltatee.com> <20190131185656.17972-3-logang@deltatee.com> <20190131223932.GR229773@google.com> <74993e67-cdc5-234a-d26c-5c0177a0299a@deltatee.com> Message-ID: <20190201192323.GS229773@google.com> Content-Type: text/plain; charset="UTF-8" Message-ID: <20190201192323.gEauakk3mrprrTUtlI9skgjIWVhiTgKp7VH-LbK-fKA@z> On Thu, Jan 31, 2019@03:52:09PM -0700, Logan Gunthorpe wrote: > On 2019-01-31 3:39 p.m., Bjorn Helgaas wrote: > >> diff --git a/include/linux/msi.h b/include/linux/msi.h > >> index 784fb52b9900..6458ab049852 100644 > >> --- a/include/linux/msi.h > >> +++ b/include/linux/msi.h > >> @@ -88,6 +88,7 @@ struct msi_desc { > >> __u8 multi_cap : 3; > >> __u8 maskbit : 1; > >> __u8 is_64 : 1; > >> + __u8 is_virtual : 1; > > > > You did the right thing by using the same style as what's already > > here, but does anybody know why are we using __u8 and __u16 here? > > > > Those typedefs are in include/uapi/asm-generic/int-l64.h, which > > suggests they're for things exported to user space, but I don't think > > that's the case here, so I'm wondering if we could someday replace > > these with u8 and u16. Obviously that wouldn't be part of *this* > > series. > > Yes, I was also confused by this. But I always follow the "when-in-rome" > rule. Thanks for following the "when-in-rome" rule. That seems so obvious that it wouldn't even need to be written down, but it is often ignored. > My understanding is the same as yours is that __u8 should be used > for userspace compatibility which doesn't apply here. If there is > consensus on this being wrong, I'd be happy to write a cleanup patch > that fixes it separate from this series. That'd be awesome. There are also a couple more in pci-driver.c that could be fixed at the same time. Bjorn