| Message ID | 1459525755-36968-7-git-send-email-shannon.zhao@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Shannon, Sorry to come late in the review process. On 01/04/2016 16:49, Shannon Zhao wrote: > Add a bus_notifier for platform bus device in order to map the device > mmio regions when DOM0 booting with ACPI. > > Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> > Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > --- > drivers/xen/Makefile | 1 + > drivers/xen/arm-device.c | 141 +++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 142 insertions(+) > create mode 100644 drivers/xen/arm-device.c > > diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile > index 9b7a35c..415f286 100644 > --- a/drivers/xen/Makefile > +++ b/drivers/xen/Makefile > @@ -9,6 +9,7 @@ CFLAGS_features.o := $(nostackp) > > CFLAGS_efi.o += -fshort-wchar > > +dom0-$(CONFIG_ARM64) += arm-device.o > dom0-$(CONFIG_PCI) += pci.o > dom0-$(CONFIG_USB_SUPPORT) += dbgp.o > dom0-$(CONFIG_XEN_ACPI) += acpi.o $(xen-pad-y) > diff --git a/drivers/xen/arm-device.c b/drivers/xen/arm-device.c > new file mode 100644 > index 0000000..76e26e5 > --- /dev/null > +++ b/drivers/xen/arm-device.c > @@ -0,0 +1,141 @@ > +/* > + * Copyright (c) 2015, Linaro Limited, Shannon Zhao > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/platform_device.h> > +#include <linux/acpi.h> > +#include <xen/xen.h> > +#include <xen/page.h> > +#include <xen/interface/memory.h> > +#include <asm/xen/hypervisor.h> > +#include <asm/xen/hypercall.h> > + > +static int xen_unmap_device_mmio(struct resource *resource, unsigned int count) NITs: There is multiple resource so s/resource/resources/. Also the variable could be const. > +{ > + unsigned int i, j, nr; > + int rc = 0; > + struct resource *r; > + struct xen_remove_from_physmap xrp; > + > + for (i = 0; i < count; i++) { > + r = &resource[i]; > + nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE); > + if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0)) > + continue; > + > + for (j = 0; j < nr; j++) { > + xrp.domid = DOMID_SELF; > + xrp.gpfn = XEN_PFN_DOWN(r->start) + j; > + rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, > + &xrp); > + if (rc) > + return rc; > + } > + } > + > + return rc; > +} > + > +static int xen_map_device_mmio(struct resource *resource, unsigned int count) Ditto > +{ > + unsigned int i, j, nr; > + int rc = 0; > + struct resource *r; > + xen_pfn_t *gpfns; > + xen_ulong_t *idxs; > + int *errs; > + struct xen_add_to_physmap_range xatp; > + > + for (i = 0; i < count; i++) { > + r = &resource[i]; > + nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE); > + if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0)) > + continue; > + > + gpfns = kzalloc(sizeof(xen_pfn_t) * nr, GFP_KERNEL); > + idxs = kzalloc(sizeof(xen_ulong_t) * nr, GFP_KERNEL); > + errs = kzalloc(sizeof(int) * nr, GFP_KERNEL); > + if (!gpfns || !idxs || !errs) { > + kfree(gpfns); > + kfree(idxs); > + kfree(errs); > + return -ENOMEM; > + } > + > + for (j = 0; j < nr; j++) { I would add a comment to explain that the regions are always mapped 1:1 to DOM0, and this is fine because the memory map for DOM0 is the same as the host (except for the RAM). > + gpfns[j] = XEN_PFN_DOWN(r->start) + j; > + idxs[j] = XEN_PFN_DOWN(r->start) + j; > + } > + > + xatp.domid = DOMID_SELF; > + xatp.size = nr; > + xatp.space = XENMAPSPACE_dev_mmio; > + > + set_xen_guest_handle(xatp.gpfns, gpfns); > + set_xen_guest_handle(xatp.idxs, idxs); > + set_xen_guest_handle(xatp.errs, errs); > + > + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp); > + kfree(gpfns); > + kfree(idxs); > + kfree(errs); > + if (rc) > + return rc; Shouldn't we redo the mapping if the hypercall fails? > + } > + > + return rc; > +} > + > +static int xen_platform_notifier(struct notifier_block *nb, > + unsigned long action, void *data) > +{ > + struct platform_device *pdev = to_platform_device(data); > + int r = 0; > + > + if (pdev->num_resources == 0 || pdev->resource == NULL) > + return NOTIFY_OK; > + > + switch (action) { > + case BUS_NOTIFY_ADD_DEVICE: > + r = xen_map_device_mmio(pdev->resource, pdev->num_resources); > + break; > + case BUS_NOTIFY_DEL_DEVICE: > + r = xen_unmap_device_mmio(pdev->resource, pdev->num_resources); > + break; > + default: > + return NOTIFY_DONE; > + } > + if (r) > + dev_err(&pdev->dev, "Platform: Failed to %s device %s MMIO!\n", > + action == BUS_NOTIFY_ADD_DEVICE ? "map" : > + (action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"), > + pdev->name); > + > + return NOTIFY_OK; > +} > + > +static struct notifier_block platform_device_nb = { > + .notifier_call = xen_platform_notifier, > +}; > + > +static int __init register_xen_platform_notifier(void) > +{ > + if (!xen_initial_domain() || acpi_disabled) > + return 0; > + > + return bus_register_notifier(&platform_bus_type, &platform_device_nb); > +} > + > +arch_initcall(register_xen_platform_notifier); > Regards,
On 2016/4/6 20:16, Julien Grall wrote: >> + gpfns[j] = XEN_PFN_DOWN(r->start) + j; >> + idxs[j] = XEN_PFN_DOWN(r->start) + j; >> + } >> + >> + xatp.domid = DOMID_SELF; >> + xatp.size = nr; >> + xatp.space = XENMAPSPACE_dev_mmio; >> + >> + set_xen_guest_handle(xatp.gpfns, gpfns); >> + set_xen_guest_handle(xatp.idxs, idxs); >> + set_xen_guest_handle(xatp.errs, errs); >> + >> + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp); >> + kfree(gpfns); >> + kfree(idxs); >> + kfree(errs); >> + if (rc) >> + return rc; > > Shouldn't we redo the mapping if the hypercall fails? Hmm, why? If it fails again when we redo the mapping, what should we do then? Redo again? I think if it fails at the first time it will always fail no matter how many times we do. Thanks,
Hi Shannon, On 07/04/16 02:37, Shannon Zhao wrote: > > > On 2016/4/6 20:16, Julien Grall wrote: >>> + gpfns[j] = XEN_PFN_DOWN(r->start) + j; >>> + idxs[j] = XEN_PFN_DOWN(r->start) + j; >>> + } >>> + >>> + xatp.domid = DOMID_SELF; >>> + xatp.size = nr; >>> + xatp.space = XENMAPSPACE_dev_mmio; >>> + >>> + set_xen_guest_handle(xatp.gpfns, gpfns); >>> + set_xen_guest_handle(xatp.idxs, idxs); >>> + set_xen_guest_handle(xatp.errs, errs); >>> + >>> + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp); >>> + kfree(gpfns); >>> + kfree(idxs); >>> + kfree(errs); >>> + if (rc) >>> + return rc; >> >> Shouldn't we redo the mapping if the hypercall fails? > Hmm, why? If it fails again when we redo the mapping, what should we do > then? Redo again? Because the device MMIO region is left half mapped in DOM0 address space. After having another look to your patch, if an error occurs, the notifier will still return NOTIFY_OK. This will lead to random data abort when the driver is accessing the MMIO regions as the device will be considered fully functional. However, even if the notifier return NOTIFY_BAD, the function device_add doesn't care about the return value of blocking_notifier_call_chain. I think this need to be fixed. > I think if it fails at the first time it will always fail no matter how > many times we do. I was speaking about the mappings that succeeded. They will unlikely fail during removal. If they ever fail you can just ignore the error. Regards,
On 2016/4/7 18:32, Julien Grall wrote: > Hi Shannon, > > On 07/04/16 02:37, Shannon Zhao wrote: >> >> >> On 2016/4/6 20:16, Julien Grall wrote: >>>> + gpfns[j] = XEN_PFN_DOWN(r->start) + j; >>>> + idxs[j] = XEN_PFN_DOWN(r->start) + j; >>>> + } >>>> + >>>> + xatp.domid = DOMID_SELF; >>>> + xatp.size = nr; >>>> + xatp.space = XENMAPSPACE_dev_mmio; >>>> + >>>> + set_xen_guest_handle(xatp.gpfns, gpfns); >>>> + set_xen_guest_handle(xatp.idxs, idxs); >>>> + set_xen_guest_handle(xatp.errs, errs); >>>> + >>>> + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp); >>>> + kfree(gpfns); >>>> + kfree(idxs); >>>> + kfree(errs); >>>> + if (rc) >>>> + return rc; >>> >>> Shouldn't we redo the mapping if the hypercall fails? >> Hmm, why? If it fails again when we redo the mapping, what should we do >> then? Redo again? > > Because the device MMIO region is left half mapped in DOM0 address space. > > After having another look to your patch, if an error occurs, the > notifier will still return NOTIFY_OK. This will lead to random data > abort when the driver is accessing the MMIO regions as the device will > be considered fully functional. > > However, even if the notifier return NOTIFY_BAD, the function device_add > doesn't care about the return value of blocking_notifier_call_chain. I > think this need to be fixed. > >> I think if it fails at the first time it will always fail no matter how >> many times we do. > > I was speaking about the mappings that succeeded. They will unlikely > fail during removal. If they ever fail you can just ignore the error. Ok, I see. I thought you mean that it needs to map the regions again. But what you really mean is undoing the mappings. Thanks,
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile index 9b7a35c..415f286 100644 --- a/drivers/xen/Makefile +++ b/drivers/xen/Makefile @@ -9,6 +9,7 @@ CFLAGS_features.o := $(nostackp) CFLAGS_efi.o += -fshort-wchar +dom0-$(CONFIG_ARM64) += arm-device.o dom0-$(CONFIG_PCI) += pci.o dom0-$(CONFIG_USB_SUPPORT) += dbgp.o dom0-$(CONFIG_XEN_ACPI) += acpi.o $(xen-pad-y) diff --git a/drivers/xen/arm-device.c b/drivers/xen/arm-device.c new file mode 100644 index 0000000..76e26e5 --- /dev/null +++ b/drivers/xen/arm-device.c @@ -0,0 +1,141 @@ +/* + * Copyright (c) 2015, Linaro Limited, Shannon Zhao + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/platform_device.h> +#include <linux/acpi.h> +#include <xen/xen.h> +#include <xen/page.h> +#include <xen/interface/memory.h> +#include <asm/xen/hypervisor.h> +#include <asm/xen/hypercall.h> + +static int xen_unmap_device_mmio(struct resource *resource, unsigned int count) +{ + unsigned int i, j, nr; + int rc = 0; + struct resource *r; + struct xen_remove_from_physmap xrp; + + for (i = 0; i < count; i++) { + r = &resource[i]; + nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE); + if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0)) + continue; + + for (j = 0; j < nr; j++) { + xrp.domid = DOMID_SELF; + xrp.gpfn = XEN_PFN_DOWN(r->start) + j; + rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, + &xrp); + if (rc) + return rc; + } + } + + return rc; +} + +static int xen_map_device_mmio(struct resource *resource, unsigned int count) +{ + unsigned int i, j, nr; + int rc = 0; + struct resource *r; + xen_pfn_t *gpfns; + xen_ulong_t *idxs; + int *errs; + struct xen_add_to_physmap_range xatp; + + for (i = 0; i < count; i++) { + r = &resource[i]; + nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE); + if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0)) + continue; + + gpfns = kzalloc(sizeof(xen_pfn_t) * nr, GFP_KERNEL); + idxs = kzalloc(sizeof(xen_ulong_t) * nr, GFP_KERNEL); + errs = kzalloc(sizeof(int) * nr, GFP_KERNEL); + if (!gpfns || !idxs || !errs) { + kfree(gpfns); + kfree(idxs); + kfree(errs); + return -ENOMEM; + } + + for (j = 0; j < nr; j++) { + gpfns[j] = XEN_PFN_DOWN(r->start) + j; + idxs[j] = XEN_PFN_DOWN(r->start) + j; + } + + xatp.domid = DOMID_SELF; + xatp.size = nr; + xatp.space = XENMAPSPACE_dev_mmio; + + set_xen_guest_handle(xatp.gpfns, gpfns); + set_xen_guest_handle(xatp.idxs, idxs); + set_xen_guest_handle(xatp.errs, errs); + + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp); + kfree(gpfns); + kfree(idxs); + kfree(errs); + if (rc) + return rc; + } + + return rc; +} + +static int xen_platform_notifier(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct platform_device *pdev = to_platform_device(data); + int r = 0; + + if (pdev->num_resources == 0 || pdev->resource == NULL) + return NOTIFY_OK; + + switch (action) { + case BUS_NOTIFY_ADD_DEVICE: + r = xen_map_device_mmio(pdev->resource, pdev->num_resources); + break; + case BUS_NOTIFY_DEL_DEVICE: + r = xen_unmap_device_mmio(pdev->resource, pdev->num_resources); + break; + default: + return NOTIFY_DONE; + } + if (r) + dev_err(&pdev->dev, "Platform: Failed to %s device %s MMIO!\n", + action == BUS_NOTIFY_ADD_DEVICE ? "map" : + (action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"), + pdev->name); + + return NOTIFY_OK; +} + +static struct notifier_block platform_device_nb = { + .notifier_call = xen_platform_notifier, +}; + +static int __init register_xen_platform_notifier(void) +{ + if (!xen_initial_domain() || acpi_disabled) + return 0; + + return bus_register_notifier(&platform_bus_type, &platform_device_nb); +} + +arch_initcall(register_xen_platform_notifier);