| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <b7adb3d8-f965-6e9f-5701-48778b5e8beb@epam.com>
Date: Thu, 30 Sep 2021 07:30:39 +0000
From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@...m.com>
To: "jgross@...e.com" <jgross@...e.com>
CC: "boris.ostrovsky@...cle.com" <boris.ostrovsky@...cle.com>,
"julien@....org" <julien@....org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"sstabellini@...nel.org" <sstabellini@...nel.org>,
"jbeulich@...e.com" <jbeulich@...e.com>,
Oleksandr Andrushchenko <Oleksandr_Andrushchenko@...m.com>,
Anastasiia Lukianenko <Anastasiia_Lukianenko@...m.com>,
"xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>
Subject: Re: [PATCH v5] xen-pciback: allow compiling on other archs than x86
Hi, Juergen!
Is it good to go or we need some other changes?
Thank you,
Oleksandr
On 28.09.21 10:35, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
>
> Xen-pciback driver was designed to be built for x86 only. But it
> can also be used by other architectures, e.g. Arm.
>
> Currently PCI backend implements multiple functionalities at a time,
> such as:
> 1. It is used as a database for assignable PCI devices, e.g. xl
> pci-assignable-{add|remove|list} manipulates that list. So, whenever
> the toolstack needs to know which PCI devices can be passed through
> it reads that from the relevant sysfs entries of the pciback.
> 2. It is used to hold the unbound PCI devices list, e.g. when passing
> through a PCI device it needs to be unbound from the relevant device
> driver and bound to pciback (strictly speaking it is not required
> that the device is bound to pciback, but pciback is again used as a
> database of the passed through PCI devices, so we can re-bind the
> devices back to their original drivers when guest domain shuts down)
> 3. Device reset for the devices being passed through
> 4. Para-virtualised use-cases support
>
> The para-virtualised part of the driver is not always needed as some
> architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
> model for PCI device passthrough.
>
> For such use-cases make the very first step in splitting the
> xen-pciback driver into two parts: Xen PCI stub and PCI PV backend
> drivers.
>
> For that add new configuration options CONFIG_XEN_PCI_STUB and
> CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its
> functionality, e.g. no support for para-virtualised scenario.
> x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the
> fully featured backend driver.
>
> Please note, that CONFIG_XEN_PCIDEV_BACKEND and CONFIG_XEN_PCIDEV_STUB
> are mutually exclusive.
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
> Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@...m.com>
> Reviewed-by: Stefano Stabellini <sstabellini@...nel.org>
> ---
> Changes since v4:
> - squashed two patches
> - added comments to Makefile
> Changes since v3:
> - Fix >>32 shift for 32-bit architectures
> Changes since v2:
> - swap the patch order
> Since v1:
> - Do not move pci_xen_initial_domain as it is x86 specific
> ---
> arch/x86/include/asm/xen/pci.h | 16 -----
> arch/x86/pci/xen.c | 74 +-------------------
> drivers/xen/Kconfig | 24 +++++++
> drivers/xen/Makefile | 2 +-
> drivers/xen/pci.c | 75 +++++++++++++++++++++
> drivers/xen/xen-pciback/Makefile | 7 ++
> drivers/xen/xen-pciback/conf_space_header.c | 8 ++-
> drivers/xen/xen-pciback/pci_stub.c | 3 +-
> drivers/xen/xen-pciback/pciback.h | 5 ++
> drivers/xen/xen-pciback/xenbus.c | 8 ++-
> include/xen/pci.h | 28 ++++++++
> 11 files changed, 155 insertions(+), 95 deletions(-)
> create mode 100644 include/xen/pci.h
>
> diff --git a/arch/x86/include/asm/xen/pci.h b/arch/x86/include/asm/xen/pci.h
> index 3506d8c598c1..4b08c2b809ea 100644
> --- a/arch/x86/include/asm/xen/pci.h
> +++ b/arch/x86/include/asm/xen/pci.h
> @@ -16,27 +16,11 @@ static inline int pci_xen_hvm_init(void)
> #endif
> #if defined(CONFIG_XEN_DOM0)
> int __init pci_xen_initial_domain(void);
> -int xen_find_device_domain_owner(struct pci_dev *dev);
> -int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain);
> -int xen_unregister_device_domain_owner(struct pci_dev *dev);
> #else
> static inline int __init pci_xen_initial_domain(void)
> {
> return -1;
> }
> -static inline int xen_find_device_domain_owner(struct pci_dev *dev)
> -{
> - return -1;
> -}
> -static inline int xen_register_device_domain_owner(struct pci_dev *dev,
> - uint16_t domain)
> -{
> - return -1;
> -}
> -static inline int xen_unregister_device_domain_owner(struct pci_dev *dev)
> -{
> - return -1;
> -}
> #endif
>
> #if defined(CONFIG_PCI_MSI)
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 3d41a09c2c14..4a45b0bf9ae4 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -23,6 +23,7 @@
>
> #include <xen/features.h>
> #include <xen/events.h>
> +#include <xen/pci.h>
> #include <asm/xen/pci.h>
> #include <asm/xen/cpuid.h>
> #include <asm/apic.h>
> @@ -583,77 +584,4 @@ int __init pci_xen_initial_domain(void)
> }
> return 0;
> }
> -
> -struct xen_device_domain_owner {
> - domid_t domain;
> - struct pci_dev *dev;
> - struct list_head list;
> -};
> -
> -static DEFINE_SPINLOCK(dev_domain_list_spinlock);
> -static struct list_head dev_domain_list = LIST_HEAD_INIT(dev_domain_list);
> -
> -static struct xen_device_domain_owner *find_device(struct pci_dev *dev)
> -{
> - struct xen_device_domain_owner *owner;
> -
> - list_for_each_entry(owner, &dev_domain_list, list) {
> - if (owner->dev == dev)
> - return owner;
> - }
> - return NULL;
> -}
> -
> -int xen_find_device_domain_owner(struct pci_dev *dev)
> -{
> - struct xen_device_domain_owner *owner;
> - int domain = -ENODEV;
> -
> - spin_lock(&dev_domain_list_spinlock);
> - owner = find_device(dev);
> - if (owner)
> - domain = owner->domain;
> - spin_unlock(&dev_domain_list_spinlock);
> - return domain;
> -}
> -EXPORT_SYMBOL_GPL(xen_find_device_domain_owner);
> -
> -int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain)
> -{
> - struct xen_device_domain_owner *owner;
> -
> - owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);
> - if (!owner)
> - return -ENODEV;
> -
> - spin_lock(&dev_domain_list_spinlock);
> - if (find_device(dev)) {
> - spin_unlock(&dev_domain_list_spinlock);
> - kfree(owner);
> - return -EEXIST;
> - }
> - owner->domain = domain;
> - owner->dev = dev;
> - list_add_tail(&owner->list, &dev_domain_list);
> - spin_unlock(&dev_domain_list_spinlock);
> - return 0;
> -}
> -EXPORT_SYMBOL_GPL(xen_register_device_domain_owner);
> -
> -int xen_unregister_device_domain_owner(struct pci_dev *dev)
> -{
> - struct xen_device_domain_owner *owner;
> -
> - spin_lock(&dev_domain_list_spinlock);
> - owner = find_device(dev);
> - if (!owner) {
> - spin_unlock(&dev_domain_list_spinlock);
> - return -ENODEV;
> - }
> - list_del(&owner->list);
> - spin_unlock(&dev_domain_list_spinlock);
> - kfree(owner);
> - return 0;
> -}
> -EXPORT_SYMBOL_GPL(xen_unregister_device_domain_owner);
> #endif
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 22f5aff0c136..75b9330dc6fd 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -181,10 +181,34 @@ config SWIOTLB_XEN
> select DMA_OPS
> select SWIOTLB
>
> +config XEN_PCI_STUB
> + bool
> +
> +config XEN_PCIDEV_STUB
> + tristate "Xen PCI-device stub driver"
> + depends on PCI && !X86 && XEN
> + depends on XEN_BACKEND
> + select XEN_PCI_STUB
> + default m
> + help
> + The PCI device stub driver provides limited version of the PCI
> + device backend driver without para-virtualized support for guests.
> + If you select this to be a module, you will need to make sure no
> + other driver has bound to the device(s) you want to make visible to
> + other guests.
> +
> + The "hide" parameter (only applicable if backend driver is compiled
> + into the kernel) allows you to bind the PCI devices to this module
> + from the default device drivers. The argument is the list of PCI BDFs:
> + xen-pciback.hide=(03:00.0)(04:00.0)
> +
> + If in doubt, say m.
> +
> config XEN_PCIDEV_BACKEND
> tristate "Xen PCI-device backend driver"
> depends on PCI && X86 && XEN
> depends on XEN_BACKEND
> + select XEN_PCI_STUB
> default m
> help
> The PCI device backend driver allows the kernel to export arbitrary
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index 3434593455b2..5aae66e638a7 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -24,7 +24,7 @@ obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o
> obj-$(CONFIG_XEN_PVHVM_GUEST) += platform-pci.o
> obj-$(CONFIG_SWIOTLB_XEN) += swiotlb-xen.o
> obj-$(CONFIG_XEN_MCE_LOG) += mcelog.o
> -obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback/
> +obj-$(CONFIG_XEN_PCI_STUB) += xen-pciback/
> obj-$(CONFIG_XEN_PRIVCMD) += xen-privcmd.o
> obj-$(CONFIG_XEN_ACPI_PROCESSOR) += xen-acpi-processor.o
> obj-$(CONFIG_XEN_EFI) += efi.o
> diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
> index 224df03ce42e..fc8c1249d49f 100644
> --- a/drivers/xen/pci.c
> +++ b/drivers/xen/pci.c
> @@ -254,3 +254,78 @@ static int xen_mcfg_late(void)
> return 0;
> }
> #endif
> +
> +#ifdef CONFIG_XEN_DOM0
> +struct xen_device_domain_owner {
> + domid_t domain;
> + struct pci_dev *dev;
> + struct list_head list;
> +};
> +
> +static DEFINE_SPINLOCK(dev_domain_list_spinlock);
> +static struct list_head dev_domain_list = LIST_HEAD_INIT(dev_domain_list);
> +
> +static struct xen_device_domain_owner *find_device(struct pci_dev *dev)
> +{
> + struct xen_device_domain_owner *owner;
> +
> + list_for_each_entry(owner, &dev_domain_list, list) {
> + if (owner->dev == dev)
> + return owner;
> + }
> + return NULL;
> +}
> +
> +int xen_find_device_domain_owner(struct pci_dev *dev)
> +{
> + struct xen_device_domain_owner *owner;
> + int domain = -ENODEV;
> +
> + spin_lock(&dev_domain_list_spinlock);
> + owner = find_device(dev);
> + if (owner)
> + domain = owner->domain;
> + spin_unlock(&dev_domain_list_spinlock);
> + return domain;
> +}
> +EXPORT_SYMBOL_GPL(xen_find_device_domain_owner);
> +
> +int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain)
> +{
> + struct xen_device_domain_owner *owner;
> +
> + owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);
> + if (!owner)
> + return -ENODEV;
> +
> + spin_lock(&dev_domain_list_spinlock);
> + if (find_device(dev)) {
> + spin_unlock(&dev_domain_list_spinlock);
> + kfree(owner);
> + return -EEXIST;
> + }
> + owner->domain = domain;
> + owner->dev = dev;
> + list_add_tail(&owner->list, &dev_domain_list);
> + spin_unlock(&dev_domain_list_spinlock);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(xen_register_device_domain_owner);
> +
> +int xen_unregister_device_domain_owner(struct pci_dev *dev)
> +{
> + struct xen_device_domain_owner *owner;
> +
> + spin_lock(&dev_domain_list_spinlock);
> + owner = find_device(dev);
> + if (!owner) {
> + spin_unlock(&dev_domain_list_spinlock);
> + return -ENODEV;
> + }
> + list_del(&owner->list);
> + spin_unlock(&dev_domain_list_spinlock);
> + kfree(owner);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(xen_unregister_device_domain_owner);
> +#endif
> diff --git a/drivers/xen/xen-pciback/Makefile b/drivers/xen/xen-pciback/Makefile
> index e8d981d43235..d63df09de81c 100644
> --- a/drivers/xen/xen-pciback/Makefile
> +++ b/drivers/xen/xen-pciback/Makefile
> @@ -1,5 +1,12 @@
> # SPDX-License-Identifier: GPL-2.0
> +
> +# N.B. The below cannot be expressed with a single line using
> +# CONFIG_XEN_PCI_STUB as it always remains in "y" state,
> +# thus preventing the driver to be built as a module.
> +# Please note, that CONFIG_XEN_PCIDEV_BACKEND and
> +# CONFIG_XEN_PCIDEV_STUB are mutually exclusive.
> obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback.o
> +obj-$(CONFIG_XEN_PCIDEV_STUB) += xen-pciback.o
>
> xen-pciback-y := pci_stub.o pciback_ops.o xenbus.o
> xen-pciback-y += conf_space.o conf_space_header.o \
> diff --git a/drivers/xen/xen-pciback/conf_space_header.c b/drivers/xen/xen-pciback/conf_space_header.c
> index ac45cdc38e85..981435103af1 100644
> --- a/drivers/xen/xen-pciback/conf_space_header.c
> +++ b/drivers/xen/xen-pciback/conf_space_header.c
> @@ -236,8 +236,12 @@ static void *bar_init(struct pci_dev *dev, int offset)
> else {
> pos = (offset - PCI_BASE_ADDRESS_0) / 4;
> if (pos && (res[pos - 1].flags & IORESOURCE_MEM_64)) {
> - bar->val = res[pos - 1].start >> 32;
> - bar->len_val = -resource_size(&res[pos - 1]) >> 32;
> + /*
> + * Use ">> 16 >> 16" instead of direct ">> 32" shift
> + * to avoid warnings on 32-bit architectures.
> + */
> + bar->val = res[pos - 1].start >> 16 >> 16;
> + bar->len_val = -resource_size(&res[pos - 1]) >> 16 >> 16;
> return bar;
> }
> }
> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
> index f8e4faa96ad6..bba527620507 100644
> --- a/drivers/xen/xen-pciback/pci_stub.c
> +++ b/drivers/xen/xen-pciback/pci_stub.c
> @@ -19,7 +19,8 @@
> #include <linux/sched.h>
> #include <linux/atomic.h>
> #include <xen/events.h>
> -#include <asm/xen/pci.h>
> +#include <xen/pci.h>
> +#include <xen/xen.h>
> #include <asm/xen/hypervisor.h>
> #include <xen/interface/physdev.h>
> #include "pciback.h"
> diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h
> index 95e28ee48d52..9a64196e831d 100644
> --- a/drivers/xen/xen-pciback/pciback.h
> +++ b/drivers/xen/xen-pciback/pciback.h
> @@ -71,6 +71,11 @@ 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)
> +{
> + return IS_ENABLED(CONFIG_XEN_PCIDEV_BACKEND);
> +}
> +
> /* Ensure a device is turned off or reset */
> void xen_pcibk_reset_device(struct pci_dev *pdev);
>
> diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
> index c09c7ebd6968..bde63ef677b8 100644
> --- a/drivers/xen/xen-pciback/xenbus.c
> +++ b/drivers/xen/xen-pciback/xenbus.c
> @@ -14,7 +14,7 @@
> #include <linux/workqueue.h>
> #include <xen/xenbus.h>
> #include <xen/events.h>
> -#include <asm/xen/pci.h>
> +#include <xen/pci.h>
> #include "pciback.h"
>
> #define INVALID_EVTCHN_IRQ (-1)
> @@ -743,6 +743,9 @@ const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
>
> int __init xen_pcibk_xenbus_register(void)
> {
> + if (!xen_pcibk_pv_support())
> + return 0;
> +
> xen_pcibk_backend = &xen_pcibk_vpci_backend;
> if (passthrough)
> xen_pcibk_backend = &xen_pcibk_passthrough_backend;
> @@ -752,5 +755,6 @@ int __init xen_pcibk_xenbus_register(void)
>
> void __exit xen_pcibk_xenbus_unregister(void)
> {
> - xenbus_unregister_driver(&xen_pcibk_driver);
> + if (xen_pcibk_pv_support())
> + xenbus_unregister_driver(&xen_pcibk_driver);
> }
> diff --git a/include/xen/pci.h b/include/xen/pci.h
> new file mode 100644
> index 000000000000..b8337cf85fd1
> --- /dev/null
> +++ b/include/xen/pci.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __XEN_PCI_H__
> +#define __XEN_PCI_H__
> +
> +#if defined(CONFIG_XEN_DOM0)
> +int xen_find_device_domain_owner(struct pci_dev *dev);
> +int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain);
> +int xen_unregister_device_domain_owner(struct pci_dev *dev);
> +#else
> +static inline int xen_find_device_domain_owner(struct pci_dev *dev)
> +{
> + return -1;
> +}
> +
> +static inline int xen_register_device_domain_owner(struct pci_dev *dev,
> + uint16_t domain)
> +{
> + return -1;
> +}
> +
> +static inline int xen_unregister_device_domain_owner(struct pci_dev *dev)
> +{
> + return -1;
> +}
> +#endif
> +
> +#endif
Powered by blists - more mailing lists