On Wed, Jul 29, 2015 at 03:55:14PM +0300, Pavel Fedin wrote:
> Expansion of [*] suffix is very slow because index expansion is done using
> trial and error strategy, starting every time from zero and retrying with
> the next index until insertion succeeds. With large number of already added
> properties this process takes huge amount of time (O(n^2) complexity).
>
> Some architectures (like ARM) use very large amount of IRQ pins in interrupt
> controller models. This flaw makes machine startup extremely slow
> (~20 seconds for ARM64 with 32 CPUs. This patch decreases this time down to
> ~10 seconds.
>
> Signed-off-by: Pavel Fedin <p.fe...@samsung.com>
> ---
> hw/core/qdev.c | 29 ++++++++++++++++++++++++-----
> 1 file changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index b2f404a..d285784 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -25,6 +25,8 @@
> inherit from a particular bus (e.g. PCI or I2C) rather than
> this API directly. */
>
> +#include <glib/gprintf.h>
> +
> #include "hw/qdev.h"
> #include "hw/fw-path-provider.h"
> #include "sysemu/sysemu.h"
> @@ -415,15 +417,24 @@ static NamedGPIOList
> *qdev_get_named_gpio_list(DeviceState *dev,
> void qdev_init_gpio_in_named(DeviceState *dev, qemu_irq_handler handler,
> const char *name, int n)
> {
> - int i;
> + int i, l;
> NamedGPIOList *gpio_list = qdev_get_named_gpio_list(dev, name);
> - char *propname = g_strdup_printf("%s[*]", name ? name :
> "unnamed-gpio-in");
> + char *propname;
>
> assert(gpio_list->num_out == 0 || !name);
> +
> + if (!name) {
> + name = "unnamed-gpio-in";
> + }
> + l = strlen(name);
> + propname = g_malloc(l + 13); /* 10 characters for UINT_MAX plus "[]" */
> + memcpy(propname, name, l);
Please don't do manual string length calculations in combination with
unbounded sprintf calls. It is a recipe for future security bugs.
> +
> gpio_list->in = qemu_extend_irqs(gpio_list->in, gpio_list->num_in,
> handler,
> dev, n);
>
> for (i = gpio_list->num_in; i < gpio_list->num_in + n; i++) {
> + g_sprintf(&propname[l], "[%u]", i);
Replace this with
gchar *propname = g_strdup_printf("%s[%u]", name, i)
> object_property_add_child(OBJECT(dev), propname,
> OBJECT(gpio_list->in[i]), &error_abort);
g_free(propname);
> }
> @@ -440,14 +451,21 @@ void qdev_init_gpio_in(DeviceState *dev,
> qemu_irq_handler handler, int n)
> void qdev_init_gpio_out_named(DeviceState *dev, qemu_irq *pins,
> const char *name, int n)
> {
> - int i;
> + int i, l;
> NamedGPIOList *gpio_list = qdev_get_named_gpio_list(dev, name);
> - char *propname = g_strdup_printf("%s[*]", name ? name :
> "unnamed-gpio-out");
> + char *propname;
>
> assert(gpio_list->num_in == 0 || !name);
> - gpio_list->num_out += n;
> +
> + if (!name) {
> + name = "unnamed-gpio-out";
> + }
> + l = strlen(name);
> + propname = g_malloc(l + 13); /* 10 characters for UINT_MAX plus "[]" */
> + memcpy(propname, name, l);
Same again here.
>
> for (i = 0; i < n; ++i) {
> + g_sprintf(&propname[l], "[%u]", gpio_list->num_out + i);
> memset(&pins[i], 0, sizeof(*pins));
> object_property_add_link(OBJECT(dev), propname, TYPE_IRQ,
> (Object **)&pins[i],
> @@ -456,6 +474,7 @@ void qdev_init_gpio_out_named(DeviceState *dev, qemu_irq
> *pins,
> &error_abort);
> }
> g_free(propname);
> + gpio_list->num_out += n;
> }
Regards,
Daniel
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