Re: [Qemu-devel] [PATCH v2 07/16] hw/intc/arm_gic: Make ICDDCR/GICD_CTLR banked

[Peter Maydell]

On 30 October 2014 at 22:12, Greg Bellows <address@hidden> wrote:
> From: Fabian Aggeler <address@hidden>
>
> ICDDCR/GICD_CTLR is banked in GICv1 implementations with Security
> Extensions or in GICv2 in independent from Security Extensions.
> This makes it possible to enable forwarding of interrupts from
> Distributor to the CPU interfaces for Group0 and Group1.
>
> EnableGroup0 (Bit [1]) in GICv1 is IMPDEF. Since this bit (Enable
> Non-secure) is present in the integrated IC of the Cortex-A9 MPCore,
> which implements the GICv1 profile, we support this bit in GICv1 too.
>
> Signed-off-by: Fabian Aggeler <address@hidden>
>
> ---
>
> v1 -> v2
> - Fix gic_dist_writeb() update of GICD_CTRL to only use bit[0] of the
>   EnableGrp1 field not bit[1].
> - Add clarifying comments
> ---
>  hw/intc/arm_gic.c                | 49 
> ++++++++++++++++++++++++++++++++++++----
>  hw/intc/arm_gic_common.c         |  2 +-
>  include/hw/intc/arm_gic_common.h |  7 +++++-
>  3 files changed, 52 insertions(+), 6 deletions(-)
>
> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
> index 36ac188..1db15aa 100644
> --- a/hw/intc/arm_gic.c
> +++ b/hw/intc/arm_gic.c
> @@ -302,8 +302,25 @@ static uint32_t gic_dist_readb(void *opaque, hwaddr 
> offset)
>      cpu = gic_get_current_cpu(s);
>      cm = 1 << cpu;
>      if (offset < 0x100) {
> -        if (offset == 0)
> -            return s->enabled;
> +        if (offset == 0) {      /* GICD_CTLR */
> +            res = 0;
> +            if ((s->revision == 2 && !s->security_extn)
> +                    || (s->security_extn && !ns_access())) {
> +                /* In this case the GICD_CTRL contains both a group0 and 
> group1

Typo: should be _CTLR.

> +                 * enable bit, so we create the resuling value by aggregating
> +                 * the bits from the two enable values.
> +                 * The group0 enable bit is only visible to secure accesses.
> +                 * The group1 enable bit (bit[1]) is an alias of bit[0] in
> +                 * the non-secure copy (enabled_grp[1]).
> +                 */
> +                res = (s->enabled_grp[1] << 1) | s->enabled_grp[0];
> +            } else if (s->security_extn && ns_access()) {
> +                res = s->enabled_grp[1];
> +            } else {
> +                /* Neither GICv2 nor Security Extensions present */
> +                res = s->enabled;
> +            }
> +        }
>          if (offset == 4)
>              /* Interrupt Controller Type Register */
>              return ((s->num_irq / 32) - 1)
> @@ -471,8 +488,32 @@ static void gic_dist_writeb(void *opaque, hwaddr offset,
>      cpu = gic_get_current_cpu(s);
>      if (offset < 0x100) {
>          if (offset == 0) {
> -            s->enabled = (value & 1);
> -            DPRINTF("Distribution %sabled\n", s->enabled ? "En" : "Dis");
> +            if ((s->revision == 2 && !s->security_extn)
> +                    || (s->security_extn && !ns_access())) {
> +                s->enabled_grp[0] = value & (1U << 0); /* EnableGrp0 */
> +                /* For a GICv1 with Security Extn "EnableGrp1" is IMPDEF. */
> +                /* We only use the first bit of the enabled_grp vars to
> +                 * indicate enabled or disabled.  In this case we have to 
> shift
> +                 * the incoming value down to the low bit because the group1
> +                 * enabled bit is bit[1] in the secure/GICv2 GICD_CTLR..

Typo: repeated '.'.

> +                 */
> +                s->enabled_grp[1] = (value >> 1) & 0x1; /* EnableGrp1 */
> +                DPRINTF("Group0 distribution %sabled\n"
> +                        "Group1 distribution %sabled\n",
> +                                        s->enabled_grp[0] ? "En" : "Dis",
> +                                        s->enabled_grp[1] ? "En" : "Dis");
> +            } else if (s->security_extn && ns_access()) {
> +                /* If we are non-secure only the group1 enable bit is visible
> +                 * as bit[0] in the GICD_CTLR.
> +                 */
> +                s->enabled_grp[1] = (value & 0x1);
> +                DPRINTF("Group1 distribution %sabled\n",
> +                        s->enabled_grp[1] ? "En" : "Dis");
> +            } else {
> +                /* Neither GICv2 nor Security Extensions present */
> +                s->enabled = (value & 0x1);
> +                DPRINTF("Distribution %sabled\n", s->enabled ? "En" : "Dis");
> +            }
>          } else if (offset < 4) {
>              /* ignored.  */
>          } else if (offset >= 0x80) {
> diff --git a/hw/intc/arm_gic_common.c b/hw/intc/arm_gic_common.c
> index 28f3b2a..c44050d 100644
> --- a/hw/intc/arm_gic_common.c
> +++ b/hw/intc/arm_gic_common.c
> @@ -64,7 +64,7 @@ static const VMStateDescription vmstate_gic = {
>      .pre_save = gic_pre_save,
>      .post_load = gic_post_load,
>      .fields = (VMStateField[]) {
> -        VMSTATE_BOOL(enabled, GICState),
> +        VMSTATE_UINT8_ARRAY(enabled_grp, GICState, GIC_NR_GROUP),
>          VMSTATE_BOOL_ARRAY(cpu_enabled, GICState, GIC_NCPU),
>          VMSTATE_STRUCT_ARRAY(irq_state, GICState, GIC_MAXIRQ, 1,
>                               vmstate_gic_irq_state, gic_irq_state),
> diff --git a/include/hw/intc/arm_gic_common.h 
> b/include/hw/intc/arm_gic_common.h
> index b78981e..16e193d 100644
> --- a/include/hw/intc/arm_gic_common.h
> +++ b/include/hw/intc/arm_gic_common.h
> @@ -30,6 +30,8 @@
>  #define GIC_NR_SGIS 16
>  /* Maximum number of possible CPU interfaces, determined by GIC architecture 
> */
>  #define GIC_NCPU 8
> +/* Number of Groups (Group0 [Secure], Group1 [Non-secure]) */
> +#define GIC_NR_GROUP 2
>
>  #define MAX_NR_GROUP_PRIO 128
>  #define GIC_NR_APRS (MAX_NR_GROUP_PRIO / 32)
> @@ -52,7 +54,10 @@ typedef struct GICState {
>
>      qemu_irq parent_irq[GIC_NCPU];
>      qemu_irq parent_fiq[GIC_NCPU];
> -    bool enabled;
> +    union {
> +        uint8_t enabled;
> +        uint8_t enabled_grp[GIC_NR_GROUP]; /* EnableGrp0 and EnableGrp1 */
> +    };

Rather than a union, we should just make the code
use enabled_grp[0] when there's no grouping enabled.

>      bool cpu_enabled[GIC_NCPU];
>
>      gic_irq_state irq_state[GIC_MAXIRQ];
> --
> 1.8.3.2
>

-- PMM