Re: [Qemu-devel] [PATCH] hw: Add test device for unittests execution v2

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Wed, Aug 31, 2011 at 06:06:09PM -0300, Lucas Meneghel Rodrigues wrote:
> Add a test device which supports the kvmctl ioports,
> for running the KVM test suite.
> 
> Usage:
> 
>   qemu
>      -chardev file,path=/log/file/some/where,id=testlog
>      -device pc-testdev,chardev=testlog
> 
> lmr: I've tried to address the comments made by the
> reviewers, but I probably left out some things. Please
> let me know whether this is on the right track.
> 
> Thanks to Marcelo for helping me with questions about
> the new memory API.
> 
> Changes from v1:
>  * Updated description
>  * Used the API fw_cfg to retrieve device ram size in k-u-t.git (see
>  * separate patch)
>  * Use getpagesize() to retrieve page size instead of hard coding it
>  * Dropped functions to write to a serial device
>  * Updated struct name to be TestDev to comply with CODING_STYLE
>  * Now device is called pc-testdev rather than testdev
>  * Conversion to MemoryRegion
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
> ---
>  Makefile.target |    1 +
>  hw/pc-testdev.c |  121 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 122 insertions(+), 0 deletions(-)
>  create mode 100644 hw/pc-testdev.c
> 
> diff --git a/Makefile.target b/Makefile.target
> index 07af4d4..450fc18 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -232,6 +232,7 @@ obj-i386-y += debugcon.o multiboot.o
>  obj-i386-y += pc_piix.o
>  obj-i386-$(CONFIG_KVM) += kvmclock.o
>  obj-i386-$(CONFIG_SPICE) += qxl.o qxl-logger.o qxl-render.o
> +obj-i386-y += pc-testdev.o
>  
>  # shared objects
>  obj-ppc-y = ppc.o
> diff --git a/hw/pc-testdev.c b/hw/pc-testdev.c
> new file mode 100644
> index 0000000..0b6dd96
> --- /dev/null
> +++ b/hw/pc-testdev.c
> @@ -0,0 +1,121 @@
> +#include <sys/mman.h>
> +#include "hw.h"
> +#include "qdev.h"
> +#include "isa.h"
> +#include "fw_cfg.h"
> +#include "exec-memory.h"
> +
> +struct TestDev {
> +    ISADevice dev;
> +    CharDriverState *chr;
> +    MemoryRegion mem;
> +};
> +
> +static void test_device_exit(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    exit(data);
> +}
> +
> +static void test_device_irq_line(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    qemu_set_irq(isa_get_irq(addr - 0x2000), !!data);
> +}
> +
> +static uint32 test_device_ioport_data;
> +
> +static void test_device_ioport_write(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    test_device_ioport_data = data;
> +}
> +
> +static uint32_t test_device_ioport_read(void *opaque, uint32_t addr)
> +{
> +    return test_device_ioport_data;
> +}
> +
> +static void test_device_flush_page(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    target_phys_addr_t len = getpagesize();
> +    void *a = cpu_physical_memory_map(data & ~0xffful, &len, 0);
> +
> +    mprotect(a, 4096, PROT_NONE);
> +    mprotect(a, 4096, PROT_READ|PROT_WRITE);
> +    cpu_physical_memory_unmap(a, len, 0, 0);
> +}
> +
> +static char *iomem_buf;
> +
> +static uint32_t test_iomem_readb(void *opaque, target_phys_addr_t addr)
> +{
> +    return iomem_buf[addr];
> +}
> +
> +static uint32_t test_iomem_readw(void *opaque, target_phys_addr_t addr)
> +{
> +    return *(uint16_t*)(iomem_buf + addr);
> +}
> +
> +static uint32_t test_iomem_readl(void *opaque, target_phys_addr_t addr)
> +{
> +    return *(uint32_t*)(iomem_buf + addr);
> +}
> +
> +static void test_iomem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    iomem_buf[addr] = val;
> +}
> +
> +static void test_iomem_writew(void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    *(uint16_t*)(iomem_buf + addr) = val;
> +}
> +
> +static void test_iomem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
> +{
> +    *(uint32_t*)(iomem_buf + addr) = val;
> +}
> +
> +static const MemoryRegionOps test_mem_ops = {
> +    .old_mmio = {
> +    .read = { test_iomem_readb, test_iomem_readw, test_iomem_readl },
> +    .write = { test_iomem_writeb, test_iomem_writew, test_iomem_writel },
> +    },
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +
> +static int init_test_device(ISADevice *isa)
> +{
> +    struct TestDev *dev = DO_UPCAST(struct TestDev, dev, isa);
> +
> +    register_ioport_write(0xf4, 1, 4, test_device_exit, dev);
> +    register_ioport_read(0xe0, 1, 1, test_device_ioport_read, dev);
> +    register_ioport_write(0xe0, 1, 1, test_device_ioport_write, dev);
> +    register_ioport_read(0xe0, 1, 2, test_device_ioport_read, dev);
> +    register_ioport_write(0xe0, 1, 2, test_device_ioport_write, dev);
> +    register_ioport_read(0xe0, 1, 4, test_device_ioport_read, dev);
> +    register_ioport_write(0xe0, 1, 4, test_device_ioport_write, dev);
> +    register_ioport_write(0xe4, 1, 4, test_device_flush_page, dev);
> +    register_ioport_write(0x2000, 24, 1, test_device_irq_line, NULL);

Hi,

I think you should address Blue Swirls comment and add indirection
to avoid the need to allocate large number of ports. If the number grows
significantly it will become a problem. Something as simple as an
addr port combined with an access port will do. Then the device can
decode it into the specific operations internally.

And I still don't understand why we cant use MMIO, so that archs without
ioports can use this. Or does that cause other problems?

Cheers