[RFC PATCH 1/4] xen: Introduce physaddr_abi CDF flag

["Teddy Astie" <teddy.astie@xxxxxxxxxx>]

Introduce the physaddr_abi flag to indicate that the guest uses
physical addresses (gpaddr) instead of virtual addresses when
performing hypercalls.

Signed-off-by: Teddy Astie <teddy.astie@xxxxxxxxxx>
---
 xen/common/domain.c         | 10 +++++++++-
 xen/include/public/domctl.h |  4 +++-
 xen/include/xen/sched.h     |  6 ++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 585fd726a9..1a1e51c32d 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -716,12 +716,14 @@ static int sanitise_domain_config(struct 
xen_domctl_createdomain *config)
     bool hap = config->flags & XEN_DOMCTL_CDF_hap;
     bool iommu = config->flags & XEN_DOMCTL_CDF_iommu;
     bool vpmu = config->flags & XEN_DOMCTL_CDF_vpmu;
+    bool physaddr_abi = config->flags & XEN_DOMCTL_CDF_physaddr_abi;
 
     if ( config->flags &
          ~(XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap |
            XEN_DOMCTL_CDF_s3_integrity | XEN_DOMCTL_CDF_oos_off |
            XEN_DOMCTL_CDF_xs_domain | XEN_DOMCTL_CDF_iommu |
-           XEN_DOMCTL_CDF_nested_virt | XEN_DOMCTL_CDF_vpmu) )
+           XEN_DOMCTL_CDF_nested_virt | XEN_DOMCTL_CDF_vpmu |
+           XEN_DOMCTL_CDF_physaddr_abi) )
     {
         dprintk(XENLOG_INFO, "Unknown CDF flags %#x\n", config->flags);
         return -EINVAL;
@@ -745,6 +747,12 @@ static int sanitise_domain_config(struct 
xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( physaddr_abi && !hvm )
+    {
+        dprintk(XENLOG_INFO, "Physical address ABI requested for non-HVM 
guest");
+        return -EINVAL;
+    }
+
     if ( iommu )
     {
         if ( config->iommu_opts & ~XEN_DOMCTL_IOMMU_no_sharept )
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 5b2063eed9..3a77efe673 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -66,9 +66,11 @@ struct xen_domctl_createdomain {
 #define XEN_DOMCTL_CDF_nested_virt    (1U << _XEN_DOMCTL_CDF_nested_virt)
 /* Should we expose the vPMU to the guest? */
 #define XEN_DOMCTL_CDF_vpmu           (1U << 7)
+/* Do the guest use physical addresses for hypercalls ? */
+#define XEN_DOMCTL_CDF_physaddr_abi   (1U << 8)
 
 /* Max XEN_DOMCTL_CDF_* constant.  Used for ABI checking. */
-#define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_vpmu
+#define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_physaddr_abi
 
     uint32_t flags;
 
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 559d201e0c..a29c63c737 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -1201,6 +1201,12 @@ static always_inline bool hap_enabled(const struct 
domain *d)
         evaluate_nospec(d->options & XEN_DOMCTL_CDF_hap);
 }
 
+static always_inline bool is_hvm_physaddr_abi(const struct domain *d)
+{
+    return IS_ENABLED(CONFIG_HVM) &&
+        evaluate_nospec(d->options & XEN_DOMCTL_CDF_physaddr_abi);
+}
+
 static inline bool is_hwdom_pinned_vcpu(const struct vcpu *v)
 {
     return (is_hardware_domain(v->domain) &&
-- 
2.47.2



Teddy Astie | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech