From 2356f15caefc0cc63d9cc5122641754f76ef9b25 Mon Sep 17 00:00:00 2001 From: Frediano Ziglio Date: Thu, 27 Feb 2025 14:50:15 +0000 Subject: xen: Add support for XenServer 6.1 platform device On XenServer on Windows machine a platform device with ID 2 instead of 1 is used. This device is mainly identical to device 1 but due to some Windows update behaviour it was decided to use a device with a different ID. This causes compatibility issues with Linux which expects, if Xen is detected, to find a Xen platform device (5853:0001) otherwise code will crash due to some missing initialization (specifically grant tables). Specifically from dmesg RIP: 0010:gnttab_expand+0x29/0x210 Code: 90 0f 1f 44 00 00 55 31 d2 48 89 e5 41 57 41 56 41 55 41 89 fd 41 54 53 48 83 ec 10 48 8b 05 7e 9a 49 02 44 8b 35 a7 9a 49 02 <8b> 48 04 8d 44 39 ff f7 f1 45 8d 24 06 89 c3 e8 43 fe ff ff 44 39 RSP: 0000:ffffba34c01fbc88 EFLAGS: 00010086 ... The device 2 is presented by Xapi adding device specification to Qemu command line. Signed-off-by: Frediano Ziglio Acked-by: Juergen Gross Message-ID: <20250227145016.25350-1-frediano.ziglio@cloud.com> Signed-off-by: Juergen Gross --- drivers/xen/platform-pci.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c index 544d3f9010b9..1db82da56db6 100644 --- a/drivers/xen/platform-pci.c +++ b/drivers/xen/platform-pci.c @@ -26,6 +26,8 @@ #define DRV_NAME "xen-platform-pci" +#define PCI_DEVICE_ID_XEN_PLATFORM_XS61 0x0002 + static unsigned long platform_mmio; static unsigned long platform_mmio_alloc; static unsigned long platform_mmiolen; @@ -174,6 +176,8 @@ pci_out: static const struct pci_device_id platform_pci_tbl[] = { {PCI_VENDOR_ID_XEN, PCI_DEVICE_ID_XEN_PLATFORM, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0}, + {PCI_VENDOR_ID_XEN, PCI_DEVICE_ID_XEN_PLATFORM_XS61, + PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0}, {0,} }; -- cgit v1.2.3 From 1c3dfc7c6b0f551fdca3f7c1f1e4c73be8adb17d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 10 Mar 2025 15:22:38 -0700 Subject: xen/mcelog: Add __nonstring annotations for unterminated strings When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to and correctly identify the char array as "not a C string" and thereby eliminate the warning. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1] Cc: Juergen Gross Cc: Stefano Stabellini Cc: Oleksandr Tyshchenko Cc: xen-devel@lists.xenproject.org Signed-off-by: Kees Cook Acked-by: Juergen Gross Message-ID: <20250310222234.work.473-kees@kernel.org> Signed-off-by: Juergen Gross --- include/xen/interface/xen-mca.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/xen/interface/xen-mca.h b/include/xen/interface/xen-mca.h index 464aa6b3a5f9..1c9afbe8cc26 100644 --- a/include/xen/interface/xen-mca.h +++ b/include/xen/interface/xen-mca.h @@ -372,7 +372,7 @@ struct xen_mce { #define XEN_MCE_LOG_LEN 32 struct xen_mce_log { - char signature[12]; /* "MACHINECHECK" */ + char signature[12] __nonstring; /* "MACHINECHECK" */ unsigned len; /* = XEN_MCE_LOG_LEN */ unsigned next; unsigned flags; -- cgit v1.2.3 From 5c4e79e29a9fe4ea132118ac40c2bc97cfe23077 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 12 Mar 2025 16:32:45 +0100 Subject: xenfs/xensyms: respect hypervisor's "next" indication The interface specifies the symnum field as an input and output; the hypervisor sets it to the next sequential symbol's index. xensyms_next() incrementing the position explicitly (and xensyms_next_sym() decrementing it to "rewind") is only correct as long as the sequence of symbol indexes is non-sparse. Use the hypervisor-supplied value instead to update the position in xensyms_next(), and use the saved incoming index in xensyms_next_sym(). Cc: stable@kernel.org Fixes: a11f4f0a4e18 ("xen: xensyms support") Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Message-ID: <15d5e7fa-ec5d-422f-9319-d28bed916349@suse.com> Signed-off-by: Juergen Gross --- drivers/xen/xenfs/xensyms.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xenfs/xensyms.c b/drivers/xen/xenfs/xensyms.c index b799bc759c15..088b7f02c358 100644 --- a/drivers/xen/xenfs/xensyms.c +++ b/drivers/xen/xenfs/xensyms.c @@ -48,7 +48,7 @@ static int xensyms_next_sym(struct xensyms *xs) return -ENOMEM; set_xen_guest_handle(symdata->name, xs->name); - symdata->symnum--; /* Rewind */ + symdata->symnum = symnum; /* Rewind */ ret = HYPERVISOR_platform_op(&xs->op); if (ret < 0) @@ -78,7 +78,7 @@ static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos) { struct xensyms *xs = m->private; - xs->op.u.symdata.symnum = ++(*pos); + *pos = xs->op.u.symdata.symnum; if (xensyms_next_sym(xs)) return NULL; -- cgit v1.2.3 From 421d62f47b7a61794f04ddd9ec2e4fa2e209da90 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Fri, 7 Mar 2025 00:47:36 +0000 Subject: xen/pciback: Remove unused pcistub_get_pci_dev pcistub_get_pci_dev() was added in 2009 as part of: commit 30edc14bf39a ("xen/pciback: xen pci backend driver.") Remove it. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juergen Gross Message-ID: <20250307004736.291229-1-linux@treblig.org> Signed-off-by: Juergen Gross --- drivers/xen/xen-pciback/pci_stub.c | 20 -------------------- drivers/xen/xen-pciback/pciback.h | 2 -- 2 files changed, 22 deletions(-) diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c index b616b7768c3b..5c2f829d5b0b 100644 --- a/drivers/xen/xen-pciback/pci_stub.c +++ b/drivers/xen/xen-pciback/pci_stub.c @@ -262,26 +262,6 @@ struct pci_dev *pcistub_get_pci_dev_by_slot(struct xen_pcibk_device *pdev, return found_dev; } -struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev, - struct pci_dev *dev) -{ - struct pcistub_device *psdev; - struct pci_dev *found_dev = NULL; - unsigned long flags; - - spin_lock_irqsave(&pcistub_devices_lock, flags); - - list_for_each_entry(psdev, &pcistub_devices, dev_list) { - if (psdev->dev == dev) { - found_dev = pcistub_device_get_pci_dev(pdev, psdev); - break; - } - } - - spin_unlock_irqrestore(&pcistub_devices_lock, flags); - return found_dev; -} - /* * Called when: * - XenBus state has been reconfigure (pci unplug). See xen_pcibk_remove_device diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h index f9599ed2f2e2..b786c1f74f85 100644 --- a/drivers/xen/xen-pciback/pciback.h +++ b/drivers/xen/xen-pciback/pciback.h @@ -67,8 +67,6 @@ extern struct list_head xen_pcibk_quirks; struct pci_dev *pcistub_get_pci_dev_by_slot(struct xen_pcibk_device *pdev, int domain, int bus, int slot, int func); -struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev, - struct pci_dev *dev); void pcistub_put_pci_dev(struct pci_dev *dev); static inline bool xen_pcibk_pv_support(void) -- cgit v1.2.3 From 5ccf1b8ae76ddf348e02a0d1564ff9baf8b6c415 Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Wed, 19 Feb 2025 10:20:55 +0100 Subject: xen/pci: Do not register devices with segments >= 0x10000 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current hypercall interface for doing PCI device operations always uses a segment field that has a 16 bit width. However on Linux there are buses like VMD that hook up devices into the PCI hierarchy at segment >= 0x10000, after the maximum possible segment enumerated in ACPI. Attempting to register or manage those devices with Xen would result in errors at best, or overlaps with existing devices living on the truncated equivalent segment values. Note also that the VMD segment numbers are arbitrarily assigned by the OS, and hence there would need to be some negotiation between Xen and the OS to agree on how to enumerate VMD segments and devices behind them. Skip notifying Xen about those devices. Given how VMD bridges can multiplex interrupts on behalf of devices behind them there's no need for Xen to be aware of such devices for them to be usable by Linux. Signed-off-by: Roger Pau Monné Acked-by: Juergen Gross Message-ID: <20250219092059.90850-2-roger.pau@citrix.com> Signed-off-by: Juergen Gross --- drivers/xen/pci.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c index 416f231809cb..bfe07adb3e3a 100644 --- a/drivers/xen/pci.c +++ b/drivers/xen/pci.c @@ -43,6 +43,18 @@ static int xen_add_device(struct device *dev) pci_mcfg_reserved = true; } #endif + + if (pci_domain_nr(pci_dev->bus) >> 16) { + /* + * The hypercall interface is limited to 16bit PCI segment + * values, do not attempt to register devices with Xen in + * segments greater or equal than 0x10000. + */ + dev_info(dev, + "not registering with Xen: invalid PCI segment\n"); + return 0; + } + if (pci_seg_supported) { DEFINE_RAW_FLEX(struct physdev_pci_device_add, add, optarr, 1); @@ -149,6 +161,16 @@ static int xen_remove_device(struct device *dev) int r; struct pci_dev *pci_dev = to_pci_dev(dev); + if (pci_domain_nr(pci_dev->bus) >> 16) { + /* + * The hypercall interface is limited to 16bit PCI segment + * values. + */ + dev_info(dev, + "not unregistering with Xen: invalid PCI segment\n"); + return 0; + } + if (pci_seg_supported) { struct physdev_pci_device device = { .seg = pci_domain_nr(pci_dev->bus), @@ -182,6 +204,16 @@ int xen_reset_device(const struct pci_dev *dev) .flags = PCI_DEVICE_RESET_FLR, }; + if (pci_domain_nr(dev->bus) >> 16) { + /* + * The hypercall interface is limited to 16bit PCI segment + * values. + */ + dev_info(&dev->dev, + "unable to notify Xen of device reset: invalid PCI segment\n"); + return 0; + } + return HYPERVISOR_physdev_op(PHYSDEVOP_pci_device_reset, &device); } EXPORT_SYMBOL_GPL(xen_reset_device); -- cgit v1.2.3 From 6c4d5aadf5df31ea0ac025980670eee9beaf466b Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Wed, 19 Feb 2025 10:20:56 +0100 Subject: PCI: vmd: Disable MSI remapping bypass under Xen MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit MSI remapping bypass (directly configuring MSI entries for devices on the VMD bus) won't work under Xen, as Xen is not aware of devices in such bus, and hence cannot configure the entries using the pIRQ interface in the PV case, and in the PVH case traps won't be setup for MSI entries for such devices. Until Xen is aware of devices in the VMD bus prevent the VMD_FEAT_CAN_BYPASS_MSI_REMAP capability from being used when running as any kind of Xen guest. The MSI remapping bypass is an optional feature of VMD bridges, and hence when running under Xen it will be masked and devices will be forced to redirect its interrupts from the VMD bridge. That mode of operation must always be supported by VMD bridges and works when Xen is not aware of devices behind the VMD bridge. Signed-off-by: Roger Pau Monné Acked-by: Bjorn Helgaas Message-ID: <20250219092059.90850-3-roger.pau@citrix.com> Signed-off-by: Juergen Gross --- drivers/pci/controller/vmd.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 9d9596947350..e619accca49d 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -17,6 +17,8 @@ #include #include +#include + #include #define VMD_CFGBAR 0 @@ -970,6 +972,24 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id) struct vmd_dev *vmd; int err; + if (xen_domain()) { + /* + * Xen doesn't have knowledge about devices in the VMD bus + * because the config space of devices behind the VMD bridge is + * not known to Xen, and hence Xen cannot discover or configure + * them in any way. + * + * Bypass of MSI remapping won't work in that case as direct + * write by Linux to the MSI entries won't result in functional + * interrupts, as Xen is the entity that manages the host + * interrupt controller and must configure interrupts. However + * multiplexing of interrupts by the VMD bridge will work under + * Xen, so force the usage of that mode which must always be + * supported by VMD bridges. + */ + features &= ~VMD_FEAT_CAN_BYPASS_MSI_REMAP; + } + if (resource_size(&dev->resource[VMD_CFGBAR]) < (1 << 20)) return -ENOMEM; -- cgit v1.2.3 From c3164d2e0d181027da8fc94f8179d8607c3d440f Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Wed, 19 Feb 2025 10:20:57 +0100 Subject: PCI/MSI: Convert pci_msi_ignore_mask to per MSI domain flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Setting pci_msi_ignore_mask inhibits the toggling of the mask bit for both MSI and MSI-X entries globally, regardless of the IRQ chip they are using. Only Xen sets the pci_msi_ignore_mask when routing physical interrupts over event channels, to prevent PCI code from attempting to toggle the maskbit, as it's Xen that controls the bit. However, the pci_msi_ignore_mask being global will affect devices that use MSI interrupts but are not routing those interrupts over event channels (not using the Xen pIRQ chip). One example is devices behind a VMD PCI bridge. In that scenario the VMD bridge configures MSI(-X) using the normal IRQ chip (the pIRQ one in the Xen case), and devices behind the bridge configure the MSI entries using indexes into the VMD bridge MSI table. The VMD bridge then demultiplexes such interrupts and delivers to the destination device(s). Having pci_msi_ignore_mask set in that scenario prevents (un)masking of MSI entries for devices behind the VMD bridge. Move the signaling of no entry masking into the MSI domain flags, as that allows setting it on a per-domain basis. Set it for the Xen MSI domain that uses the pIRQ chip, while leaving it unset for the rest of the cases. Remove pci_msi_ignore_mask at once, since it was only used by Xen code, and with Xen dropping usage the variable is unneeded. This fixes using devices behind a VMD bridge on Xen PV hardware domains. Albeit Devices behind a VMD bridge are not known to Xen, that doesn't mean Linux cannot use them. By inhibiting the usage of VMD_FEAT_CAN_BYPASS_MSI_REMAP and the removal of the pci_msi_ignore_mask bodge devices behind a VMD bridge do work fine when use from a Linux Xen hardware domain. That's the whole point of the series. Signed-off-by: Roger Pau Monné Reviewed-by: Thomas Gleixner Acked-by: Juergen Gross Acked-by: Bjorn Helgaas Message-ID: <20250219092059.90850-4-roger.pau@citrix.com> Signed-off-by: Juergen Gross --- arch/x86/pci/xen.c | 8 ++------ drivers/pci/msi/msi.c | 37 +++++++++++++++++++++---------------- include/linux/msi.h | 3 ++- kernel/irq/msi.c | 2 +- 4 files changed, 26 insertions(+), 24 deletions(-) diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c index 0f2fe524f60d..b8755cde2419 100644 --- a/arch/x86/pci/xen.c +++ b/arch/x86/pci/xen.c @@ -436,7 +436,8 @@ static struct msi_domain_ops xen_pci_msi_domain_ops = { }; static struct msi_domain_info xen_pci_msi_domain_info = { - .flags = MSI_FLAG_PCI_MSIX | MSI_FLAG_FREE_MSI_DESCS | MSI_FLAG_DEV_SYSFS, + .flags = MSI_FLAG_PCI_MSIX | MSI_FLAG_FREE_MSI_DESCS | + MSI_FLAG_DEV_SYSFS | MSI_FLAG_NO_MASK, .ops = &xen_pci_msi_domain_ops, }; @@ -484,11 +485,6 @@ static __init void xen_setup_pci_msi(void) * in allocating the native domain and never use it. */ x86_init.irqs.create_pci_msi_domain = xen_create_pci_msi_domain; - /* - * With XEN PIRQ/Eventchannels in use PCI/MSI[-X] masking is solely - * controlled by the hypervisor. - */ - pci_msi_ignore_mask = 1; } #else /* CONFIG_PCI_MSI */ diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index 2f647cac4cae..4c8c2b57b5f6 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -10,12 +10,12 @@ #include #include #include +#include #include "../pci.h" #include "msi.h" int pci_msi_enable = 1; -int pci_msi_ignore_mask; /** * pci_msi_supported - check whether MSI may be enabled on a device @@ -285,6 +285,8 @@ static void pci_msi_set_enable(struct pci_dev *dev, int enable) static int msi_setup_msi_desc(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks) { + const struct irq_domain *d = dev_get_msi_domain(&dev->dev); + const struct msi_domain_info *info = d->host_data; struct msi_desc desc; u16 control; @@ -295,8 +297,7 @@ static int msi_setup_msi_desc(struct pci_dev *dev, int nvec, /* Lies, damned lies, and MSIs */ if (dev->dev_flags & PCI_DEV_FLAGS_HAS_MSI_MASKING) control |= PCI_MSI_FLAGS_MASKBIT; - /* Respect XEN's mask disabling */ - if (pci_msi_ignore_mask) + if (info->flags & MSI_FLAG_NO_MASK) control &= ~PCI_MSI_FLAGS_MASKBIT; desc.nvec_used = nvec; @@ -604,12 +605,15 @@ static void __iomem *msix_map_region(struct pci_dev *dev, */ void msix_prepare_msi_desc(struct pci_dev *dev, struct msi_desc *desc) { + const struct irq_domain *d = dev_get_msi_domain(&dev->dev); + const struct msi_domain_info *info = d->host_data; + desc->nvec_used = 1; desc->pci.msi_attrib.is_msix = 1; desc->pci.msi_attrib.is_64 = 1; desc->pci.msi_attrib.default_irq = dev->irq; desc->pci.mask_base = dev->msix_base; - desc->pci.msi_attrib.can_mask = !pci_msi_ignore_mask && + desc->pci.msi_attrib.can_mask = !(info->flags & MSI_FLAG_NO_MASK) && !desc->pci.msi_attrib.is_virtual; if (desc->pci.msi_attrib.can_mask) { @@ -659,9 +663,6 @@ static void msix_mask_all(void __iomem *base, int tsize) u32 ctrl = PCI_MSIX_ENTRY_CTRL_MASKBIT; int i; - if (pci_msi_ignore_mask) - return; - for (i = 0; i < tsize; i++, base += PCI_MSIX_ENTRY_SIZE) writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL); } @@ -714,6 +715,8 @@ out_unlock: static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, int nvec, struct irq_affinity *affd) { + const struct irq_domain *d = dev_get_msi_domain(&dev->dev); + const struct msi_domain_info *info = d->host_data; int ret, tsize; u16 control; @@ -744,15 +747,17 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, /* Disable INTX */ pci_intx_for_msi(dev, 0); - /* - * Ensure that all table entries are masked to prevent - * stale entries from firing in a crash kernel. - * - * Done late to deal with a broken Marvell NVME device - * which takes the MSI-X mask bits into account even - * when MSI-X is disabled, which prevents MSI delivery. - */ - msix_mask_all(dev->msix_base, tsize); + if (!(info->flags & MSI_FLAG_NO_MASK)) { + /* + * Ensure that all table entries are masked to prevent + * stale entries from firing in a crash kernel. + * + * Done late to deal with a broken Marvell NVME device + * which takes the MSI-X mask bits into account even + * when MSI-X is disabled, which prevents MSI delivery. + */ + msix_mask_all(dev->msix_base, tsize); + } pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0); pcibios_free_irq(dev); diff --git a/include/linux/msi.h b/include/linux/msi.h index b10093c4d00e..59a421fc42bf 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -73,7 +73,6 @@ struct msi_msg { }; }; -extern int pci_msi_ignore_mask; /* Helper functions */ struct msi_desc; struct pci_dev; @@ -556,6 +555,8 @@ enum { MSI_FLAG_PCI_MSIX_ALLOC_DYN = (1 << 20), /* PCI MSIs cannot be steered separately to CPU cores */ MSI_FLAG_NO_AFFINITY = (1 << 21), + /* Inhibit usage of entry masking */ + MSI_FLAG_NO_MASK = (1 << 22), }; /** diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 396a067a8a56..7682c36cbccc 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -1143,7 +1143,7 @@ static bool msi_check_reservation_mode(struct irq_domain *domain, if (!(info->flags & MSI_FLAG_MUST_REACTIVATE)) return false; - if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_ignore_mask) + if (info->flags & MSI_FLAG_NO_MASK) return false; /* -- cgit v1.2.3