[PATCH 3/5] libxl / iommu / domctl: introduce XEN_DOMCTL_IOMMU_SET_ALLOCATION...

[Paul Durrant <paul@xen.org>]

From: Paul Durrant <pdurrant@amazon.com>

... sub-operation of XEN_DOMCTL_iommu_ctl.

This patch adds a new sub-operation into the domctl. The code in iommu_ctl()
is extended to call a new arch-specific iommu_set_allocation() function which
will be called with the IOMMU page-table overhead (in 4k pages) in response
to libxl issuing a new domctl via the xc_iommu_set_allocation() helper
function.

The helper function is only called in the x86 implementation of
libxl__arch_domain_create() when the calculated 'iommu_memkb' value is
non-zero. Hence the ARM implementation of iommu_set_allocation() simply
returns -EOPNOTSUPP.

NOTE: The implementation of the IOMMU page-table memory pool will be added in
      a subsequent patch and so the x86 implementation of
      iommu_set_allocation() currently does nothing other than return 0 (to
      indicate success) thereby ensuring that the new call in
      libxl__arch_domain_create() always succeeds.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Ian Jackson <iwj@xenproject.org>
Cc: Wei Liu <wl@xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <george.dunlap@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Julien Grall <julien@xen.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Anthony PERARD <anthony.perard@citrix.com>
Cc: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
---
 tools/libs/ctrl/include/xenctrl.h   |  5 +++++
 tools/libs/ctrl/xc_domain.c         | 16 ++++++++++++++++
 tools/libs/light/libxl_x86.c        | 10 ++++++++++
 xen/drivers/passthrough/iommu.c     |  8 ++++++++
 xen/drivers/passthrough/x86/iommu.c |  5 +++++
 xen/include/asm-arm/iommu.h         |  6 ++++++
 xen/include/asm-x86/iommu.h         |  2 ++
 xen/include/public/domctl.h         |  8 ++++++++
 8 files changed, 60 insertions(+)

diff --git a/tools/libs/ctrl/include/xenctrl.h b/tools/libs/ctrl/include/xenctrl.h
index 3796425e1e..4d6c9d44bc 100644
--- a/tools/libs/ctrl/include/xenctrl.h
+++ b/tools/libs/ctrl/include/xenctrl.h
@@ -2650,6 +2650,11 @@ int xc_livepatch_replace(xc_interface *xch, char *name, uint32_t timeout, uint32
 int xc_domain_cacheflush(xc_interface *xch, uint32_t domid,
                          xen_pfn_t start_pfn, xen_pfn_t nr_pfns);
 
+/* IOMMU control operations */
+
+int xc_iommu_set_allocation(xc_interface *xch, uint32_t domid,
+                            unsigned int nr_pages);
+
 /* Compat shims */
 #include "xenctrl_compat.h"
 
diff --git a/tools/libs/ctrl/xc_domain.c b/tools/libs/ctrl/xc_domain.c
index e7cea4a17d..0b20a8f2ee 100644
--- a/tools/libs/ctrl/xc_domain.c
+++ b/tools/libs/ctrl/xc_domain.c
@@ -2185,6 +2185,22 @@ int xc_domain_soft_reset(xc_interface *xch,
     domctl.domain = domid;
     return do_domctl(xch, &domctl);
 }
+
+int xc_iommu_set_allocation(xc_interface *xch, uint32_t domid,
+                            unsigned int nr_pages)
+{
+    DECLARE_DOMCTL;
+
+    memset(&domctl, 0, sizeof(domctl));
+
+    domctl.cmd = XEN_DOMCTL_iommu_ctl;
+    domctl.domain = domid;
+    domctl.u.iommu_ctl.op = XEN_DOMCTL_IOMMU_SET_ALLOCATION;
+    domctl.u.iommu_ctl.u.set_allocation.nr_pages = nr_pages;
+
+    return do_domctl(xch, &domctl);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/light/libxl_x86.c b/tools/libs/light/libxl_x86.c
index 6ec6c27c83..9631974dd6 100644
--- a/tools/libs/light/libxl_x86.c
+++ b/tools/libs/light/libxl_x86.c
@@ -520,6 +520,16 @@ int libxl__arch_domain_create(libxl__gc *gc, libxl_domain_config *d_config,
                           NULL, 0, &shadow, 0, NULL);
     }
 
+    if (d_config->b_info.iommu_memkb) {
+        unsigned int nr_pages = DIV_ROUNDUP(d_config->b_info.iommu_memkb, 4);
+
+        ret = xc_iommu_set_allocation(ctx->xch, domid, nr_pages);
+        if (ret) {
+            LOGED(ERROR, domid, "Failed to set IOMMU allocation");
+            goto out;
+        }
+    }
+
     if (d_config->c_info.type == LIBXL_DOMAIN_TYPE_PV &&
             libxl_defbool_val(d_config->b_info.u.pv.e820_host)) {
         ret = libxl__e820_alloc(gc, domid, d_config);
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index bef0405984..642d5c8331 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -515,6 +515,14 @@ static int iommu_ctl(
 
     switch ( ctl->op )
     {
+    case XEN_DOMCTL_IOMMU_SET_ALLOCATION:
+    {
+        struct xen_domctl_iommu_set_allocation *set_allocation =
+            &ctl->u.set_allocation;
+
+        rc = iommu_set_allocation(d, set_allocation->nr_pages);
+        break;
+    }
     default:
         rc = -EOPNOTSUPP;
         break;
diff --git a/xen/drivers/passthrough/x86/iommu.c b/xen/drivers/passthrough/x86/iommu.c
index f17b1820f4..b168073f10 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -134,6 +134,11 @@ void __hwdom_init arch_iommu_check_autotranslated_hwdom(struct domain *d)
         panic("PVH hardware domain iommu must be set in 'strict' mode\n");
 }
 
+int iommu_set_allocation(struct domain *d, unsigned nr_pages)
+{
+    return 0;
+}
+
 int arch_iommu_domain_init(struct domain *d)
 {
     struct domain_iommu *hd = dom_iommu(d);
diff --git a/xen/include/asm-arm/iommu.h b/xen/include/asm-arm/iommu.h
index 937edc8373..2e4735bace 100644
--- a/xen/include/asm-arm/iommu.h
+++ b/xen/include/asm-arm/iommu.h
@@ -33,6 +33,12 @@ int __must_check arm_iommu_map_page(struct domain *d, dfn_t dfn, mfn_t mfn,
 int __must_check arm_iommu_unmap_page(struct domain *d, dfn_t dfn,
                                       unsigned int *flush_flags);
 
+static inline int iommu_set_allocation(struct domain *d,
+                                       unsigned int nr_pages)
+{
+    return -EOPNOTSUPP;
+}
+
 #endif /* __ARCH_ARM_IOMMU_H__ */
 
 /*
diff --git a/xen/include/asm-x86/iommu.h b/xen/include/asm-x86/iommu.h
index 970eb06ffa..d086f564af 100644
--- a/xen/include/asm-x86/iommu.h
+++ b/xen/include/asm-x86/iommu.h
@@ -138,6 +138,8 @@ int pi_update_irte(const struct pi_desc *pi_desc, const struct pirq *pirq,
 int __must_check iommu_free_pgtables(struct domain *d);
 struct page_info *__must_check iommu_alloc_pgtable(struct domain *d);
 
+int __must_check iommu_set_allocation(struct domain *d, unsigned int nr_pages);
+
 #endif /* !__ARCH_X86_IOMMU_H__ */
 /*
  * Local variables:
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 75e855625a..6402678838 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1138,8 +1138,16 @@ struct xen_domctl_vuart_op {
 
 #define XEN_DOMCTL_IOMMU_INVALID 0
 
+#define XEN_DOMCTL_IOMMU_SET_ALLOCATION 1
+struct xen_domctl_iommu_set_allocation {
+    uint32_t nr_pages;
+};
+
 struct xen_domctl_iommu_ctl {
     uint32_t op; /* XEN_DOMCTL_IOMMU_* */
+    union {
+        struct xen_domctl_iommu_set_allocation set_allocation;
+    } u;
 };
 
 struct xen_domctl {
-- 
2.20.1