[PATCH] x86/domain: Fix struct domain memory corruption when building PV guests

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

arch_domain_create() can't blindly write into d->arch.hvm union.  Move the
logic into hvm_domain_initialise(), which involves passing config down.

Fixes: 2ce11ce249a3 ("x86/HVM: allow per-domain usage of hardware virtualized 
APIC")
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Jane Malalane <jane.malalane@xxxxxxxxxx>

This does not fix XenServer's wall of red from testing, but I have at least
figured out what's going on.  There's a piece of plain RAM in place of a
working LAPIC MMIO mapping (accelerated or otherwise), which causes HVMLoader
to spin in a tight loop waiting for CPU 1 to come up after failing to send an
INIT-SIPI-SIPI.

Sadly the fix is not as straightforward as I'd hoped, and needs more testing.
---
 xen/arch/x86/domain.c              | 8 +-------
 xen/arch/x86/hvm/hvm.c             | 9 ++++++++-
 xen/arch/x86/include/asm/hvm/hvm.h | 3 ++-
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 15e7e772012e..41e1e3f27272 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -853,7 +853,7 @@ int arch_domain_create(struct domain *d,
 
     if ( is_hvm_domain(d) )
     {
-        if ( (rc = hvm_domain_initialise(d)) != 0 )
+        if ( (rc = hvm_domain_initialise(d, config)) != 0 )
             goto fail;
     }
     else if ( is_pv_domain(d) )
@@ -885,12 +885,6 @@ int arch_domain_create(struct domain *d,
 
     d->arch.msr_relaxed = config->arch.misc_flags & XEN_X86_MSR_RELAXED;
 
-    d->arch.hvm.assisted_xapic =
-        config->arch.misc_flags & XEN_X86_ASSISTED_XAPIC;
-
-    d->arch.hvm.assisted_x2apic =
-        config->arch.misc_flags & XEN_X86_ASSISTED_X2APIC;
-
     spec_ctrl_init_domain(d);
 
     return 0;
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 6b5d585ed4cc..ae8267852013 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -576,7 +576,8 @@ static int cf_check hvm_print_line(
     return X86EMUL_OKAY;
 }
 
-int hvm_domain_initialise(struct domain *d)
+int hvm_domain_initialise(struct domain *d,
+                          struct xen_domctl_createdomain *config)
 {
     unsigned int nr_gsis;
     int rc;
@@ -597,6 +598,12 @@ int hvm_domain_initialise(struct domain *d)
     INIT_LIST_HEAD(&d->arch.hvm.mmcfg_regions);
     INIT_LIST_HEAD(&d->arch.hvm.msix_tables);
 
+    d->arch.hvm.assisted_xapic =
+        config->arch.misc_flags & XEN_X86_ASSISTED_XAPIC;
+
+    d->arch.hvm.assisted_x2apic =
+        config->arch.misc_flags & XEN_X86_ASSISTED_X2APIC;
+
     rc = create_perdomain_mapping(d, PERDOMAIN_VIRT_START, 0, NULL, NULL);
     if ( rc )
         goto fail;
diff --git a/xen/arch/x86/include/asm/hvm/hvm.h 
b/xen/arch/x86/include/asm/hvm/hvm.h
index 03096f31effa..55a53d9cac8f 100644
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -259,7 +259,8 @@ extern s8 hvm_port80_allowed;
 extern const struct hvm_function_table *start_svm(void);
 extern const struct hvm_function_table *start_vmx(void);
 
-int hvm_domain_initialise(struct domain *d);
+int hvm_domain_initialise(struct domain *d,
+                          struct xen_domctl_createdomain *config);
 void hvm_domain_relinquish_resources(struct domain *d);
 void hvm_domain_destroy(struct domain *d);
 
-- 
2.11.0