| Message ID | 1426793399-6283-15-git-send-email-julien.grall@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 31/03/15 11:46, Ian Campbell wrote: > On Thu, 2015-03-19 at 19:29 +0000, Julien Grall wrote: >> The formula of GICD_TYPER.ITLinesNumber is 32(N + 1). >> >> As the number of SPIs suppported by the domain may not be a multiple of >> 32, we have to round up the number before using it. >> >> At the same time remove the mask GICD_TYPE_LINES which is pointless. > > I presume because something else has ensured that nr_spis is less than > the maximum value represented by the mask? The number of SPIs is validated in domain_vgic_init. We would be in trouble in the IRQ guest injection if this number is too high. > >> Signed-off-by: Julien Grall <julien.grall@linaro.org> > > Acked-by: Ian Campbell <ian.campbell@citrix.com> Thanks,
diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c index 40619b2..b5a8f29 100644 --- a/xen/arch/arm/vgic-v2.c +++ b/xen/arch/arm/vgic-v2.c @@ -55,7 +55,7 @@ static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info) /* No secure world support for guests. */ vgic_lock(v); *r = ( ((v->domain->max_vcpus - 1) << GICD_TYPE_CPUS_SHIFT) ) - |( ((v->domain->arch.vgic.nr_spis / 32)) & GICD_TYPE_LINES ); + | DIV_ROUND_UP(v->domain->arch.vgic.nr_spis, 32); vgic_unlock(v); return 1; case GICD_IIDR: diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c index ec79c2a..96c1be8 100644 --- a/xen/arch/arm/vgic-v3.c +++ b/xen/arch/arm/vgic-v3.c @@ -700,7 +700,7 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, mmio_info_t *info) if ( dabt.size != DABT_WORD ) goto bad_width; /* No secure world support for guests. */ *r = ((ncpus - 1) << GICD_TYPE_CPUS_SHIFT | - ((v->domain->arch.vgic.nr_spis / 32) & GICD_TYPE_LINES)); + DIV_ROUND_UP(v->domain->arch.vgic.nr_spis, 32)); *r |= (irq_bits - 1) << GICD_TYPE_ID_BITS_SHIFT;
The formula of GICD_TYPER.ITLinesNumber is 32(N + 1). As the number of SPIs suppported by the domain may not be a multiple of 32, we have to round up the number before using it. At the same time remove the mask GICD_TYPE_LINES which is pointless. Signed-off-by: Julien Grall <julien.grall@linaro.org> --- Changes in v4: - Patch added --- xen/arch/arm/vgic-v2.c | 2 +- xen/arch/arm/vgic-v3.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)