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Re: [Qemu-devel] [PATCH] pci-testdev: add optional memory bar
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH] pci-testdev: add optional memory bar |
Date: |
Thu, 27 Sep 2018 21:11:37 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 09/27/18 14:10, Gerd Hoffmann wrote:
> Add memory bar to pci-testdev. Size is configurable using the membar
> property. Setting the size to zero (default) turns it off. Can be used
> to check whenever guests handle large pci bars correctly.
>
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
> docs/specs/pci-testdev.txt | 13 +++++++++----
> hw/misc/pci-testdev.c | 18 ++++++++++++++++++
> 2 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/docs/specs/pci-testdev.txt b/docs/specs/pci-testdev.txt
> index 128ae222ef..6b8ace1c55 100644
> --- a/docs/specs/pci-testdev.txt
> +++ b/docs/specs/pci-testdev.txt
> @@ -1,11 +1,11 @@
> pci-test is a device used for testing low level IO
>
> -device implements up to two BARs: BAR0 and BAR1.
> -Each BAR can be memory or IO. Guests must detect
> +device implements up to three BARs: BAR0, BAR1 and BAR2.
> +BAR 0+1 can be memory or IO. Guests must detect
> BAR type and act accordingly.
I suggest "Each of BAR 0+1", or "BAR 0+1 can be memory or IO
(independently of each other)".
Then we should say "must detect BAR types" (plural) as well.
>
> -Each BAR size is up to 4K bytes.
> -Each BAR starts with the following header:
> +BAR 0+1 size is up to 4K bytes.
I suggest "BAR 0+1 size is up to 4K bytes each".
> +BAR 0+1 starts with the following header:
>
> typedef struct PCITestDevHdr {
> uint8_t test; <- write-only, starts a given test number
> @@ -24,3 +24,8 @@ All registers are little endian.
> device is expected to always implement tests 0 to N on each BAR, and to add
> new
> tests with higher numbers. In this way a guest can scan test numbers until
> it
> detects an access type that it does not support on this BAR, then stop.
> +
> +BAR2 is a 64bit memory bar, without backing storage. It is disabled by
> +default and can be enabled using the membar=<size> property. This can
> +be used to test whenever guests handles pci bars of a specific (possibly
s/whenever/whether/? (I'm not sure about the intent.) My question
applies to the commit message too.
Also, "guests handle", or "a guest handles".
> +quite large) size correctly.
> diff --git a/hw/misc/pci-testdev.c b/hw/misc/pci-testdev.c
> index 32041f535f..af4d678ee4 100644
> --- a/hw/misc/pci-testdev.c
> +++ b/hw/misc/pci-testdev.c
> @@ -85,6 +85,9 @@ typedef struct PCITestDevState {
> MemoryRegion portio;
> IOTest *tests;
> int current;
> +
> + size_t membar_size;
> + MemoryRegion membar;
> } PCITestDevState;
>
> #define TYPE_PCI_TEST_DEV "pci-testdev"
> @@ -253,6 +256,15 @@ static void pci_testdev_realize(PCIDevice *pci_dev,
> Error **errp)
> pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &d->mmio);
> pci_register_bar(pci_dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &d->portio);
>
> + if (d->membar_size) {
> + memory_region_init(&d->membar, OBJECT(d), "membar", d->membar_size);
For consistency with the other two BARs, and for a more helpful "info
mtree" output, I think "membar" should be renamed to "pci-testdev-membar".
With those changes:
Reviewed-by: Laszlo Ersek <address@hidden>
For the current version (but it can be carried forward to v2):
Tested-by: Laszlo Ersek <address@hidden>
Thank you!
Laszlo
> + pci_register_bar(pci_dev, 2,
> + PCI_BASE_ADDRESS_SPACE_MEMORY |
> + PCI_BASE_ADDRESS_MEM_PREFETCH |
> + PCI_BASE_ADDRESS_MEM_TYPE_64,
> + &d->membar);
> + }
> +
> d->current = -1;
> d->tests = g_malloc0(IOTEST_MAX * sizeof *d->tests);
> for (i = 0; i < IOTEST_MAX; ++i) {
> @@ -305,6 +317,11 @@ static void qdev_pci_testdev_reset(DeviceState *dev)
> pci_testdev_reset(d);
> }
>
> +static Property pci_testdev_properties[] = {
> + DEFINE_PROP_SIZE("membar", PCITestDevState, membar_size, 0),
> + DEFINE_PROP_END_OF_LIST(),
> +};
> +
> static void pci_testdev_class_init(ObjectClass *klass, void *data)
> {
> DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -319,6 +336,7 @@ static void pci_testdev_class_init(ObjectClass *klass,
> void *data)
> dc->desc = "PCI Test Device";
> set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> dc->reset = qdev_pci_testdev_reset;
> + dc->props = pci_testdev_properties;
> }
>
> static const TypeInfo pci_testdev_info = {
>