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Message-ID: <87twu6b5yt.fsf@vitty.brq.redhat.com>
Date: Wed, 17 Jun 2015 19:27:38 +0200
From: Vitaly Kuznetsov <vkuznets@...hat.com>
To: jakeo@...rosoft.com
Cc: gregkh@...uxfoundation.org, kys@...rosoft.com,
linux-kernel@...r.kernel.org, devel@...uxdriverproject.org,
olaf@...fle.de, apw@...onical.com, haiyangz@...rosoft.com,
mebersol@...rosoft.com
Subject: Re: [PATCH v3 1/6] hv: Modify vmbus to search for all MMIO ranges available
jakeo@...rosoft.com writes:
> From: Jake Oshins <jakeo@...rosoft.com>
>
> Before this patch, hv_vmbus would search the ACPI namespace above its
> device looking for a _CRS (current resources) object, and hunt through
> the list of resources in there looking for one that described memory-
> mapped I/O space above the 4GB line. It then exported the result for
> use in the hyperv_fb (frame buffer) driver.
>
> With this patch, hv_vmbus looks for all usable MMIO ranges above 1GB
> and makes a list of them, with the highest range first in the list,
> as drivers which can allocate from that range should allocate from it.
>
> Hyperv_fb is slightly modified to use this change.
>
> This change is necessary for supporting other Hyper-V related drivers,
> which might need MMIO space below 4GB.
>
> Signed-off-by: Jake Oshins <jakeo@...rosoft.com>
> ---
> drivers/hv/vmbus_drv.c | 105 ++++++++++++++++++++++++++++++++++------
> drivers/video/fbdev/hyperv_fb.c | 2 +-
> include/linux/hyperv.h | 2 +-
> 3 files changed, 92 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index c85235e..d0e8832 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -72,10 +72,7 @@ static struct notifier_block hyperv_panic_block = {
> .notifier_call = hyperv_panic_event,
> };
>
> -struct resource hyperv_mmio = {
> - .name = "hyperv mmio",
> - .flags = IORESOURCE_MEM,
> -};
> +struct resource *hyperv_mmio;
> EXPORT_SYMBOL_GPL(hyperv_mmio);
>
> static int vmbus_exists(void)
> @@ -982,30 +979,105 @@ void vmbus_device_unregister(struct hv_device *device_obj)
>
> /*
> - * VMBUS is an acpi enumerated device. Get the the information we
> + * VMBUS is an acpi enumerated device. Get the information we
> * need from DSDT.
> */
> -
> +#define VTPM_BASE_ADDRESS 0xfed40000
> static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
> {
> + resource_size_t start = 0;
> + resource_size_t end = 0;
> + struct resource *new_res;
> + struct resource **old_res = &hyperv_mmio;
> + struct resource **prev_res = NULL;
> +
> switch (res->type) {
> case ACPI_RESOURCE_TYPE_IRQ:
> irq = res->data.irq.interrupts[0];
> + return AE_OK;
> +
> + /*
> + * "Address" descriptors are for bus windows. Ignore
> + * "memory" descriptors, which are for registers on
> + * devices.
> + */
> + case ACPI_RESOURCE_TYPE_ADDRESS32:
> + start = res->data.address32.address.minimum;
> + end = res->data.address32.address.maximum;
> break;
>
> case ACPI_RESOURCE_TYPE_ADDRESS64:
> - hyperv_mmio.start = res->data.address64.address.minimum;
> - hyperv_mmio.end = res->data.address64.address.maximum;
> + start = res->data.address64.address.minimum;
> + end = res->data.address64.address.maximum;
> break;
> +
> + default:
> + /* Unused resource type */
> + return AE_OK;
> +
> }
> + /*
> + * Ignore ranges that are below 1MB, as they're not
> + * necessary or useful here.
> + */
> + if (end < 0x100000)
> + return AE_OK;
> +
> + new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
> + if (!new_res)
> + return AE_NO_MEMORY;
> +
> + /* If this range overlaps the virtual TPM, truncate it. */
> + if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
> + end = VTPM_BASE_ADDRESS;
> +
> + new_res->name = "hyperv mmio";
> + new_res->flags = IORESOURCE_MEM;
> + new_res->start = start;
> + new_res->end = end;
> +
> + do {
> + if (!*old_res) {
> + *old_res = new_res;
> + break;
> + }
> +
> + if ((*old_res)->end < new_res->start) {
> + new_res->sibling = *old_res;
> + if (prev_res)
> + (*prev_res)->sibling = new_res;
> + *old_res = new_res;
> + break;
> + }
> +
> + prev_res = old_res;
> + old_res = &(*old_res)->sibling;
> +
> + } while (1);
>
> return AE_OK;
> }
>
> +static int vmbus_acpi_remove(struct acpi_device *device)
> +{
> + struct resource *cur_res;
> + struct resource *next_res;
> +
> + if (hyperv_mmio) {
> + for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
> + next_res = cur_res->sibling;
> + kfree(cur_res);
> + }
> + }
> +
> + return 0;
> +}
> +
> static int vmbus_acpi_add(struct acpi_device *device)
> {
> acpi_status result;
> int ret_val = -ENODEV;
> + struct acpi_device *ancestor;
>
> hv_acpi_dev = device;
>
> @@ -1015,23 +1087,25 @@ static int vmbus_acpi_add(struct acpi_device *device)
> if (ACPI_FAILURE(result))
> goto acpi_walk_err;
> /*
> - * The parent of the vmbus acpi device (Gen2 firmware) is the VMOD that
> - * has the mmio ranges. Get that.
> + * Some ancestor of the vmbus acpi device (Gen1 or Gen2
> + * firmware) is the VMOD that has the mmio ranges. Get that.
> */
> - if (device->parent) {
> - result = acpi_walk_resources(device->parent->handle,
> + for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
> + result = acpi_walk_resources(ancestor->handle,
> METHOD_NAME__CRS,
> vmbus_walk_resources, NULL);
>
> if (ACPI_FAILURE(result))
> - goto acpi_walk_err;
> - if (hyperv_mmio.start && hyperv_mmio.end)
> - request_resource(&iomem_resource, &hyperv_mmio);
> + continue;
> + if (hyperv_mmio)
> + break;
> }
> ret_val = 0;
>
> acpi_walk_err:
> complete(&probe_event);
> + if (ret_val)
> + vmbus_acpi_remove(device);
> return ret_val;
> }
>
> @@ -1047,6 +1121,7 @@ static struct acpi_driver vmbus_acpi_driver = {
> .ids = vmbus_acpi_device_ids,
> .ops = {
> .add = vmbus_acpi_add,
> + .remove = vmbus_acpi_remove,
This will probably need rebasing on top of current char-misc-next tree
as we already have commit e4ecb41c: "Drivers: hv: vmbus: introduce
vmbus_acpi_remove" there.
> },
> };
>
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> index 807ee22..b54ee1c 100644
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ b/drivers/video/fbdev/hyperv_fb.c
> @@ -688,7 +688,7 @@ static int hvfb_getmem(struct fb_info *info)
> par->mem.name = KBUILD_MODNAME;
> par->mem.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> if (gen2vm) {
> - ret = allocate_resource(&hyperv_mmio, &par->mem,
> + ret = allocate_resource(hyperv_mmio, &par->mem,
> screen_fb_size,
> 0, -1,
> screen_fb_size,
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index 902c37a..21fa867 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1245,7 +1245,7 @@ void hv_vss_deinit(void);
> void hv_vss_onchannelcallback(void *);
> void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid);
>
> -extern struct resource hyperv_mmio;
> +extern struct resource *hyperv_mmio;
>
> /*
> * Negotiated version with the Host.
--
Vitaly
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