[Xen-devel] [PATCH V6 10/10] xen/arm64: increase MAX_VIRT_CPUS to 128 on arm64

[Chen Baozi <cbz@xxxxxxxxxx>]

From: Chen Baozi <baozich@xxxxxxxxx>

After we have increased the size of GICR in address space for guest
and made use of both AFF0 and AFF1 in (v)MPIDR, we are now able to
support up to 4096 vCPUs in theory. However, it will cost 512M
address space for GICR region, which is not necessary big at the
moment. Considering the max CPU number that GIC-500 can support and
the old value of MAX_VIRT_CPUS before commit aa25a61, we increase
its value to 128.

Since the domain_max_vcpus has been changed to depends on vgic_ops,
we could have done more work in order to drop the definition of
MAX_VIRT_CPUS. However, because it is still used for some conditional
compilation in common code, I think that would be better done in a
seperate cleanup patch series.

Signed-off-by: Chen Baozi <baozich@xxxxxxxxx>
---
 xen/arch/arm/vgic-v3.c       | 1 -
 xen/include/asm-arm/config.h | 4 ++++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index 50dcfc9..2be9f81 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -895,7 +895,6 @@ static int vgic_v3_distr_mmio_write(struct vcpu *v, 
mmio_info_t *info)
         rank = vgic_rank_offset(v, 64, gicd_reg - GICD_IROUTER,
                                 DABT_DOUBLE_WORD);
         if ( rank == NULL ) goto write_ignore;
-        BUG_ON(v->domain->max_vcpus > 8);
         new_irouter = *r;
         vgic_lock_rank(v, rank, flags);
 
diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index 3b23e05..817c216 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -47,7 +47,11 @@
 #define NR_CPUS 128
 #endif
 
+#ifdef CONFIG_ARM_64
+#define MAX_VIRT_CPUS 128
+#else
 #define MAX_VIRT_CPUS 8
+#endif
 
 #define asmlinkage /* Nothing needed */
 
-- 
2.1.4


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