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Re: [PATCH v2 4/6] xen/arm: if direct-map domain use native addresses for GICv3
Hi Penny,
On 15/10/2021 04:09, Penny Zheng wrote:
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Today we use native addresses to map the GICv3 for Dom0 and fixed
addresses for DomUs.
This patch changes the behavior so that native addresses are used for
all direct-map domains(including Dom0).
Considering that dom0 may not always be directly mapped in the future,
this patch introduces a new helper "is_domain_use_host_layout()" that
wraps both two check "is_domain_direct_mapped(d) || is_hardware_domain(d)"
for more flexible useage.
Typo: s/useage/usage/
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
---
xen/arch/arm/domain_build.c | 46 +++++++++++++++++++++++++++---------
xen/arch/arm/vgic-v3.c | 20 +++++++++-------
xen/include/asm-arm/domain.h | 3 +++
3 files changed, 50 insertions(+), 19 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 6cd03e4d0f..7e0ee07e06 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2255,16 +2255,20 @@ static int __init make_gicv2_domU_node(struct
kernel_info *kinfo)
return res;
}
+#ifdef CONFIG_ARM_64
The code below is specific to the GICv3 (and not 64-bit). So this should
be gated with CONFIG_GICV3.
Personally, I would have gated the code in a separate patch. But I am
fine if this is added in this patch so long this is mentionned in the
commit message.
static int __init make_gicv3_domU_node(struct kernel_info *kinfo)
{
void *fdt = kinfo->fdt;
int res = 0;
- __be32 reg[(GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS) * 2];
+ __be32 *reg;
__be32 *cells;
+ struct domain *d = kinfo->d;
AFAICT, 'd' is not going to be modified. So please add const.
+ char buf[38];
Please explain how 38 was found. For an example, see the comment on top
of 'buf' in make_memory_node().
+ unsigned int i, len = 0;
- res = fdt_begin_node(fdt, "interrupt-controller@"__stringify(GUEST_GICV3_GICD_BASE));
- if ( res )
- return res;
+ snprintf(buf, sizeof(buf), "interrupt-controller@%"PRIx64,
+ vgic_dist_base(&d->arch.vgic));
+ res = fdt_begin_node(fdt, buf);
You set res but it gets overwritten just below. Were you meant to check
the return value?
res = fdt_property_cell(fdt, "#address-cells", 0);
if ( res )
@@ -2282,35 +2286,55 @@ static int __init make_gicv3_domU_node(struct
kernel_info *kinfo)
if ( res )
return res;
+ /* reg specifies all re-distributors and Distributor. */
+ len = (GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS) *
+ (d->arch.vgic.nr_regions + 1) * sizeof(__be32);
+ reg = xmalloc_bytes(len);
+ if ( reg == NULL )
+ return -ENOMEM;
+
cells = ®[0];
dt_child_set_range(&cells, GUEST_ROOT_ADDRESS_CELLS,
GUEST_ROOT_SIZE_CELLS,
- GUEST_GICV3_GICD_BASE, GUEST_GICV3_GICD_SIZE);
- dt_child_set_range(&cells, GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
- GUEST_GICV3_GICR0_BASE, GUEST_GICV3_GICR0_SIZE);
+ vgic_dist_base(&d->arch.vgic), GUEST_GICV3_GICD_SIZE);
- res = fdt_property(fdt, "reg", reg, sizeof(reg));
+ for ( i = 0;
+ i < d->arch.vgic.nr_regions;
+ i++, cells += (GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS) )
dt_child_set_range() will already update cells to the next ones. So this
needs to be dropped.
I was expecting this to be caugt during test. So did you test this
series with GICv3? How about the new vGIC?
+ {
+ dt_child_set_range(&cells,
+ GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
+ d->arch.vgic.rdist_regions[i].base,
+ d->arch.vgic.rdist_regions[i].size);
+ }
+
+ res = fdt_property(fdt, "reg", reg, len);
I would suggest to free 'reg' right here as you don't need it
afterwards. This will also remove the requirement to add a 'out' label
and the addition of 'goto'.
if (res)
- return res;
+ goto out;
> res = fdt_property_cell(fdt, "linux,phandle", kinfo->phandle_gic);
if (res)
- return res;
+ goto out;
res = fdt_property_cell(fdt, "phandle", kinfo->phandle_gic);
if (res)
- return res;
+ goto out;
res = fdt_end_node(fdt);
+ out:
+ xfree(reg);
return res;
}
+#endif
static int __init make_gic_domU_node(struct kernel_info *kinfo)
{
switch ( kinfo->d->arch.vgic.version )
{
+#ifdef CONFIG_ARM_64
case GIC_V3:
return make_gicv3_domU_node(kinfo);
+#endif
case GIC_V2:
return make_gicv2_domU_node(kinfo);
default:
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index cb5a70c42e..70168ca1ac 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -1641,14 +1641,15 @@ static inline unsigned int
vgic_v3_max_rdist_count(struct domain *d)
* Normally there is only one GICv3 redistributor region.
* The GICv3 DT binding provisions for multiple regions, since there are
* platforms out there which need those (multi-socket systems).
- * For Dom0 we have to live with the MMIO layout the hardware provides,
- * so we have to copy the multiple regions - as the first region may not
- * provide enough space to hold all redistributors we need.
+ * For direct-map domain(including dom0), we have to live with the MMIO
I find the sentence somewhat misleading because it implies that dom0 is
is a direct-map domain (this is true today, but this merely an
implementation details).
However, with the change below, I think it would be better to write "For
domain using the host memory layout..." and not going into details and
what sort of domain we refer to here. Instead...
+ * layout the hardware provides, so we have to copy the multiple regions
+ * - as the first region may not provide enough space to hold all
+ * redistributors we need.
* However DomU get a constructed memory map, so we can go with
* the architected single redistributor region.
*/
- return is_hardware_domain(d) ? vgic_v3_hw.nr_rdist_regions :
- GUEST_GICV3_RDIST_REGIONS;
+ return is_domain_use_host_layout(d) ? vgic_v3_hw.nr_rdist_regions :
+ GUEST_GICV3_RDIST_REGIONS;
}
static int vgic_v3_domain_init(struct domain *d)
@@ -1670,10 +1671,13 @@ static int vgic_v3_domain_init(struct domain *d)
radix_tree_init(&d->arch.vgic.pend_lpi_tree);
/*
- * Domain 0 gets the hardware address.
- * Guests get the virtual platform layout.
+ * Since we map the whole GICv3 register memory map(64KB) for
+ * all guests(including DOM0), DOM0 and direct-map guests could be
+ * treated the same way here.
+ * direct-map domain (including Dom0) gets the hardware address.
+ * Other guests get the virtual platform layout.
*/
- if ( is_hardware_domain(d) )
+ if ( is_domain_use_host_layout(d) )
{
unsigned int first_cpu = 0;
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index fc42c6a310..e8ce3ac8d2 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -32,6 +32,9 @@ enum domain_type {
/* Check if domain is direct-map memory map. */
#define is_domain_direct_mapped(d) (d->options & XEN_DOMCTL_CDF_directmap)
+#define is_domain_use_host_layout(d) (is_domain_direct_mapped(d) || \
+ is_hardware_domain(d))
... the details should be on top of this comment. The advantage is there
is less chance for a comment to rot.
Regarding the name, I would either drop the 'is_' or s/use/using/. My
preference goes for the former as it makes the name sightly shorter.
Cheers,
--
Julien Grall
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