diff mbox series

[v3,01/10] xen: introduce XEN_DOMCTL_CDF_INTERNAL_directmap

Message ID 20211116063155.901183-2-penny.zheng@arm.com (mailing list archive)
State Superseded
Headers show
Series direct-map memory map | expand

Commit Message

Penny Zheng Nov. 16, 2021, 6:31 a.m. UTC 
From: Stefano Stabellini <stefano.stabellini@xilinx.com>

This commit introduces a new arm-specific flag
XEN_DOMCTL_CDF_INTERNAL_directmap to specify that a domain should
have its memory direct-map(guest physical address == physical address)
at domain creation.

Since this flag is only available for domain created by XEN, not exposed
to the toolstack, we name it with extra "INTERNAL" to distinguish from
other public XEN_DOMCTL_CDF_xxx flags, and add comments to warn developers
not to accidently use its bitfield when introducing new
XEN_DOMCTL_CDF_xxx flag.

Refine is_domain_direct_mapped to check whether the flag
XEN_DOMCTL_CDF_INTERNAL_directmap is set.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
---
CC: andrew.cooper3@citrix.com
CC: jbeulich@suse.com
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Wei Liu <wl@xen.org>
CC: "Roger Pau Monné" <roger.pau@citrix.com>
---
v2 changes
- remove the introduce of internal flag
- remove flag direct_map since we already store this flag in d->options
- Refine is_domain_direct_mapped to check whether the flag
XEN_DOMCTL_CDF_directmap is set
- reword "1:1 direct-map" to just "direct-map"
---
v3 changes
- move flag back to xen/include/xen/domain.h, to let it be only available for
domain created by XEN.
- name it with extra "INTERNAL" and add comments to warn developers not
to accidently use its bitfield when introducing new XEN_DOMCTL_CDF_xxx flag.
- reject this flag in x86'es arch_sanitise_domain_config()
---
 xen/arch/arm/domain.c        | 3 ++-
 xen/arch/arm/domain_build.c  | 4 +++-
 xen/arch/x86/domain.c        | 6 ++++++
 xen/common/domain.c          | 3 ++-
 xen/include/asm-arm/domain.h | 4 ++--
 xen/include/public/domctl.h  | 4 ++++
 xen/include/xen/domain.h     | 3 +++
 7 files changed, 22 insertions(+), 5 deletions(-)

Comments

Jan Beulich Nov. 16, 2021, 7:54 a.m. UTC | #1 
On 16.11.2021 07:31, Penny Zheng wrote:
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -692,6 +692,12 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
>          return -EINVAL;
>      }
>  
> +    if ( config->flags & XEN_DOMCTL_CDF_INTERNAL_directmap )
> +    {
> +        dprintk(XENLOG_INFO, "direct-map cannot be enabled yet\n");
> +        return -EINVAL;
> +    }

If this flag is to be retained in its present shape, then besides
rejecting it here (or perhaps instead of, with the check here simply
becoming ASSERT()) you want to reject it in the handling of
XEN_DOMCTL_createdomain, before calling domain_create(). Only then
would the flag become truly internal.

Jan
diff mbox series

Patch

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 96e1b23550..d77265c03f 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -629,7 +629,8 @@  int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
 {
     unsigned int max_vcpus;
     unsigned int flags_required = (XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap);
-    unsigned int flags_optional = (XEN_DOMCTL_CDF_iommu | XEN_DOMCTL_CDF_vpmu);
+    unsigned int flags_optional = (XEN_DOMCTL_CDF_iommu | XEN_DOMCTL_CDF_vpmu |
+                                   XEN_DOMCTL_CDF_INTERNAL_directmap);
 
     if ( (config->flags & ~flags_optional) != flags_required )
     {
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 19487c79da..664c88ebe4 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -3089,8 +3089,10 @@  static int __init construct_dom0(struct domain *d)
 void __init create_dom0(void)
 {
     struct domain *dom0;
+    /* DOM0 has always its memory direct-map. */
     struct xen_domctl_createdomain dom0_cfg = {
-        .flags = XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap,
+        .flags = XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap |
+                 XEN_DOMCTL_CDF_INTERNAL_directmap,
         .max_evtchn_port = -1,
         .max_grant_frames = gnttab_dom0_frames(),
         .max_maptrack_frames = -1,
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index ef1812dc14..eba6502218 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -692,6 +692,12 @@  int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( config->flags & XEN_DOMCTL_CDF_INTERNAL_directmap )
+    {
+        dprintk(XENLOG_INFO, "direct-map cannot be enabled yet\n");
+        return -EINVAL;
+    }
+
     return 0;
 }
 
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 56d47dd664..13ac5950bc 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -486,7 +486,8 @@  static int sanitise_domain_config(struct xen_domctl_createdomain *config)
          ~(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_INTERNAL_directmap) )
     {
         dprintk(XENLOG_INFO, "Unknown CDF flags %#x\n", config->flags);
         return -EINVAL;
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 9b3647587a..4f2c3f09d4 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -29,8 +29,8 @@  enum domain_type {
 #define is_64bit_domain(d) (0)
 #endif
 
-/* The hardware domain has always its memory direct mapped. */
-#define is_domain_direct_mapped(d) is_hardware_domain(d)
+#define is_domain_direct_mapped(d) \
+        (d->options & XEN_DOMCTL_CDF_INTERNAL_directmap)
 
 struct vtimer {
     struct vcpu *v;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 1c21d4dc75..054e545c97 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -72,6 +72,10 @@  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)
+/*
+ * Be aware that bit 8 has already been occupied by flag
+ * XEN_DOMCTL_CDF_INTERNAL_directmap, defined in xen/include/xen/domain.h.
+ */
 
 /* Max XEN_DOMCTL_CDF_* constant.  Used for ABI checking. */
 #define XEN_DOMCTL_CDF_MAX XEN_DOMCTL_CDF_vpmu
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 160c8dbdab..2b9edfdcee 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -28,6 +28,9 @@  void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info);
 void arch_get_domain_info(const struct domain *d,
                           struct xen_domctl_getdomaininfo *info);
 
+/* Should domain memory be directly mapped? */
+#define XEN_DOMCTL_CDF_INTERNAL_directmap      (1U << 8)
+
 /*
  * Arch-specifics.
  */