Hi Paul
I may mistake, but looks like
80ff3d338dc93260b41ffeeebb0f852c2edef9ce iommu: tidy up
iommu_use_hap_pt() and need_iommu_pt_sync() macros
triggers ASSERT_UNREACHABLE on Arm if no IOMMU has been found (I built
with my platform's IOMMU driver disabled: # CONFIG_IPMMU_VMSA is not
set) .
So, iommu_setup() calls clear_iommu_hap_pt_share() with
iommu_hap_pt_share being set (CONFIG_IOMMU_FORCE_PT_SHARE=y) which,
actually, triggers ASSERT.
Here a minimal patch, leaving 'force pt share' in place. Does this
avoid the problem?
---8<---
diff --git a/xen/common/sysctl.c b/xen/common/sysctl.c
index e8763c7fdf..f88a285e7f 100644
--- a/xen/common/sysctl.c
+++ b/xen/common/sysctl.c
@@ -268,9 +268,11 @@ long
do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
pi->max_mfn = get_upper_mfn_bound();
arch_do_physinfo(pi);
if ( iommu_enabled )
+ {
pi->capabilities |= XEN_SYSCTL_PHYSCAP_directio;
- if ( iommu_hap_pt_share )
- pi->capabilities |= XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share;
+ if ( iommu_hap_pt_share )
+ pi->capabilities |=
XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share;
+ }
if ( copy_to_guest(u_sysctl, op, 1) )
ret = -EFAULT;
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 7c3003f3f1..6a10a24128 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -68,8 +68,6 @@ static inline void clear_iommu_hap_pt_share(void)
{
#ifndef iommu_hap_pt_share
iommu_hap_pt_share = false;
-#elif iommu_hap_pt_share
- ASSERT_UNREACHABLE();
#endif
}
---8<---
Paul
Thank you for the patch, but I need some time to check it (now I have
some troubles with starting guest VM). I will inform you once I check.
With the patch applied, the issue I have faced (during Xen boot) is gone
away. But, I haven't analyzed your "per-domain IOMMU control series" yet
to have opinion regarding your patch itself.
I noticed the following:
When iommu_enabled = false (my case, when IOMMU driver is disable), I
can't create guest VM if "dtdev" property is present and contains DMA
masters in the domain config:
Parsing config from /xt/dom.cfg/domd.cfg
ERROR: passthrough not supported on this platform
Even if I add passthrough = "disabled", it still denies:
Parsing config from /xt/dom.cfg/domd.cfg
ERROR: passthrough disabled but devices are specified
Looks like, correct behavior...
--
Regards,
Oleksandr Tyshchenko
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