Hi Paul,
On 14/08/2019 14:38, Paul Durrant wrote:
This patch introduces a common domain creation flag to determine whether
the domain is permitted to make use of the IOMMU. Currently the flag is
always set (for both dom0 and domU) if the IOMMU is globally enabled
(i.e. iommu_enabled == 1). sanitise_domain_config() is modified to reject
the flag if !iommu_enabled.
A new helper function, is_iommu_enabled(), is added to test the flag and
iommu_domain_init() will return immediately if !is_iommu_enabled(). This is
slightly different to the previous behaviour based on !iommu_enabled where
the call to arch_iommu_domain_init() was made regardless, however it appears
that this call was only necessary to initialize the dt_devices list for ARM
such that iommu_release_dt_devices() can be called unconditionally by
domain_relinquish_resources(). Adding a simple check of is_iommu_enabled()
into iommu_release_dt_devices() keeps this unconditional call working.
No functional change should be observed with this patch applied.
Subsequent patches will allow the toolstack to control whether use of the
IOMMU is enabled for a domain.
NOTE: The introduction of the is_iommu_enabled() helper function might
seem excessive but its use is expected to increase with subsequent
patches. Also, having iommu_domain_init() bail before calling
arch_iommu_domain_init() is not strictly necessary, but I think the
consequent addition of the call to is_iommu_enabled() in
iommu_release_dt_devices() makes the code clearer.
Signed-off-by: Paul Durrant <[email protected]>
---
Cc: Ian Jackson <[email protected]>
Cc: Wei Liu <[email protected]>
Cc: Anthony PERARD <[email protected]>
Cc: Andrew Cooper <[email protected]>
Cc: George Dunlap <[email protected]>
Cc: Jan Beulich <[email protected]>
Cc: Julien Grall <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Stefano Stabellini <[email protected]>
Cc: Tim Deegan <[email protected]>
Cc: Volodymyr Babchuk <[email protected]>
Cc: "Roger Pau Monné" <[email protected]>
Previously part of series
https://lists.xenproject.org/archives/html/xen-devel/2019-07/msg02267.html
v5:
- Move is_iommu_enabled() check into iommu_domain_init()
- Reject XEN_DOMCTL_CDF_iommu in sanitise_domain_config() if !iommu_enabled
- Use evaluate_nospec() in defintion of is_iommu_enabled()
---
tools/libxl/libxl_create.c | 8 ++++++++
xen/arch/arm/domain.c | 1 -
xen/arch/arm/setup.c | 3 +++
xen/arch/x86/setup.c | 3 +++
xen/common/domain.c | 9 ++++++++-
xen/drivers/passthrough/device_tree.c | 3 +++
xen/drivers/passthrough/iommu.c | 6 +++---
xen/include/public/domctl.h | 4 ++++
xen/include/xen/sched.h | 5 +++++
9 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 03ce166f4f..050ef042cd 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -555,6 +555,7 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config
*d_config,
.max_grant_frames = b_info->max_grant_frames,
.max_maptrack_frames = b_info->max_maptrack_frames,
};
+ libxl_physinfo physinfo;
if (info->type != LIBXL_DOMAIN_TYPE_PV) {
create.flags |= XEN_DOMCTL_CDF_hvm_guest;
@@ -564,6 +565,13 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config
*d_config,
libxl_defbool_val(info->oos) ? 0 : XEN_DOMCTL_CDF_oos_off;
}
+ rc = libxl_get_physinfo(ctx, &physinfo);
+ if (rc < 0)
+ goto out;
+
+ if (physinfo.cap_hvm_directio)
+ create.flags |= XEN_DOMCTL_CDF_iommu;
This is not going to work well on Arm as XEN_SYSCTL_PHYSCAP_directio is never
set.
+
/* Ultimately, handle is an array of 16 uint8_t, same as uuid */
libxl_uuid_copy(ctx, (libxl_uuid *)&create.handle, &info->uuid);
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 941bbff4fe..3ff19bc1ca 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -673,7 +673,6 @@ int arch_domain_create(struct domain *d,
ASSERT(config != NULL);
- /* p2m_init relies on some value initialized by the IOMMU subsystem */
Even with this patch, I still think iommu_domain_init() is required before
calling p2m_init(). For instance, this function will set the features flag.
if ( (rc = iommu_domain_init(d)) != 0 )
goto fail;
Cheers,
--
Julien Grall
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