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Re: [Xen-devel] [PATCH 1/2] xen/arm: add a warning if the guest asks for SPI delivery to vcpu != 0.

Hi Stefano,

On 25/05/14 19:06, Stefano Stabellini wrote:
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
  xen/arch/arm/vgic.c |    5 +++++
  1 file changed, 5 insertions(+)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 4869b87..e4f38a0 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -581,6 +581,11 @@ static int vgic_distr_mmio_write(struct vcpu *v, 
mmio_info_t *info)
          if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
          rank = vgic_irq_rank(v, 8, gicd_reg - GICD_ITARGETSR);
          if ( rank == NULL) goto write_ignore;
+        if ( *r )

This is wrong, ITARGETSR store a 4 bitmask of CPUs, one per interrupt. Each bit of the mask correspond to a CPU (see Table 4-17 in the GICv2 manual).

Furthermore, I think it's safe to just ignore write. The manual says:
"It is IMPLEMENTATION DEFINED which, if any, SPIs are statically configured in hardware. The CPU targets field for such an SPI is read-only, and returns a value that indicates the CPU targets for the interrupt."

With the former comment, your patch #2 is also wrong.

+        {
+            gdprintk(XENLOG_DEBUG, "SPI delivery to seconday cpus is 



Julien Grall

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