Re: [kvm-unit-tests PATCH 11/17] arm: gic: Check for validity of both group enable bits

[Alexandru Elisei <alexandru.elisei@arm.com>]

Hi,

On 11/8/19 2:42 PM, Andre Przywara wrote:
> The GIC distributor actually supports *two* enable bits, one per
> interrupt group. Linux itself won't care and will only ever use one bit.
> In a VM however we have two groups available, so we should be able to
> flip the two separate enable bits.
>
> Provide tests that try to flip the two available bits and check whether
> they stick.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  arm/gic.c            | 21 +++++++++++++++++++++
>  lib/arm/asm/gic-v3.h |  4 ++--
>  lib/arm/gic-v3.c     |  2 +-
>  3 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/arm/gic.c b/arm/gic.c
> index 485ca4f..a0511e5 100644
> --- a/arm/gic.c
> +++ b/arm/gic.c
> @@ -640,6 +640,8 @@ static void spi_test_smp(void)
>  	report("SPI delievered on all cores", cores == nr_cpus);
>  }
>  
> +#define GICD_CTLR_ENABLE_BOTH (GICD_CTLR_ENABLE_G0 | GICD_CTLR_ENABLE_G1)
> +
>  /*
>   * Check the security state configuration of the GIC.
>   * Test whether we can switch to a single security state, to test both
> @@ -694,6 +696,25 @@ static void test_irq_group(void *gicd_base)
>  			return;
>  	}
>  
> +	/* Check whether the group enable bits stick. */
> +	reg = readl(gicd_base + GICD_CTLR);
> +	writel(reg & ~GICD_CTLR_ENABLE_BOTH, gicd_base + GICD_CTLR);
> +	reg = readl(gicd_base + GICD_CTLR);
> +	report("both groups disabled sticks",
> +	       (reg & GICD_CTLR_ENABLE_BOTH) == 0);
> +
> +	reg &= ~GICD_CTLR_ENABLE_BOTH;
> +	writel(reg | GICD_CTLR_ENABLE_G1, gicd_base + GICD_CTLR);
> +	reg = readl(gicd_base + GICD_CTLR);
> +	report("group 1 enabled sticks",
> +	       (reg & GICD_CTLR_ENABLE_BOTH) == GICD_CTLR_ENABLE_G1);
> +
> +	reg &= ~GICD_CTLR_ENABLE_BOTH;
> +	writel(reg | GICD_CTLR_ENABLE_G0, gicd_base + GICD_CTLR);
> +	reg = readl(gicd_base + GICD_CTLR);
> +	report("group 0 enabled sticks",
> +	       (reg & GICD_CTLR_ENABLE_BOTH) == GICD_CTLR_ENABLE_G0);

How about adding a check that enabling both groups at the same time works?

> +
>  	/*
>  	 * On a security aware GIC in non-secure world the IGROUPR registers
>  	 * are RAZ/WI. KVM emulates a single-security-state GIC, so both
> diff --git a/lib/arm/asm/gic-v3.h b/lib/arm/asm/gic-v3.h
> index 2eaf944..0a29610 100644
> --- a/lib/arm/asm/gic-v3.h
> +++ b/lib/arm/asm/gic-v3.h
> @@ -21,8 +21,8 @@
>  #define GICD_CTLR_RWP			(1U << 31)
>  #define GICD_CTLR_DS			(1U << 6)
>  #define GICD_CTLR_ARE_NS		(1U << 4)
> -#define GICD_CTLR_ENABLE_G1A		(1U << 1)
> -#define GICD_CTLR_ENABLE_G1		(1U << 0)
> +#define GICD_CTLR_ENABLE_G1		(1U << 1)
> +#define GICD_CTLR_ENABLE_G0		(1U << 0)

Nice cleanup.

>  
>  #define GICD_IROUTER			0x6000
>  #define GICD_PIDR2			0xffe8
> diff --git a/lib/arm/gic-v3.c b/lib/arm/gic-v3.c
> index feecb5e..d6a5186 100644
> --- a/lib/arm/gic-v3.c
> +++ b/lib/arm/gic-v3.c
> @@ -42,7 +42,7 @@ void gicv3_enable_defaults(void)
>  	writel(0, dist + GICD_CTLR);
>  	gicv3_dist_wait_for_rwp();
>  
> -	writel(GICD_CTLR_ARE_NS | GICD_CTLR_ENABLE_G1A | GICD_CTLR_ENABLE_G1,
> +	writel(GICD_CTLR_ARE_NS | GICD_CTLR_ENABLE_G0 | GICD_CTLR_ENABLE_G1,
>  	       dist + GICD_CTLR);
>  	gicv3_dist_wait_for_rwp();
>  
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