Old gcc won't cope with initializers involving unnamed struct/union
fields.

Fixes: 441b1b2a50ea ("x86/emul: Switch x86_emulate_ctxt to cpu_policy")
Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/tools/fuzz/x86_instruction_emulator/fuzz-emul.c
+++ b/tools/fuzz/x86_instruction_emulator/fuzz-emul.c
@@ -893,12 +893,14 @@ int LLVMFuzzerTestOneInput(const uint8_t
     struct x86_emulate_ctxt ctxt = {
         .data = &state,
         .regs = &input.regs,
-        .cpu_policy = &cp,
         .addr_size = 8 * sizeof(void *),
         .sp_size = 8 * sizeof(void *),
     };
     int rc;
 
+    /* Not part of the initializer, for old gcc to cope. */
+    ctxt.cpu_policy = &cp;
+
     /* Reset all global state variables */
     memset(&input, 0, sizeof(input));
 
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -1313,12 +1313,14 @@ int pv_emulate_privileged_op(struct cpu_
     struct domain *currd = curr->domain;
     struct priv_op_ctxt ctxt = {
         .ctxt.regs = regs,
-        .ctxt.cpu_policy = currd->arch.cpu_policy,
         .ctxt.lma = !is_pv_32bit_domain(currd),
     };
     int rc;
     unsigned int eflags, ar;
 
+    /* Not part of the initializer, for old gcc to cope. */
+    ctxt.ctxt.cpu_policy = currd->arch.cpu_policy;
+
     if ( !pv_emul_read_descriptor(regs->cs, curr, &ctxt.cs.base,
                                   &ctxt.cs.limit, &ar, 1) ||
          !(ar & _SEGMENT_S) ||
--- a/xen/arch/x86/pv/ro-page-fault.c
+++ b/xen/arch/x86/pv/ro-page-fault.c
@@ -344,7 +344,6 @@ int pv_ro_page_fault(unsigned long addr,
     unsigned int addr_size = is_pv_32bit_domain(currd) ? 32 : BITS_PER_LONG;
     struct x86_emulate_ctxt ctxt = {
         .regs      = regs,
-        .cpu_policy = currd->arch.cpu_policy,
         .addr_size = addr_size,
         .sp_size   = addr_size,
         .lma       = addr_size > 32,
@@ -352,6 +351,9 @@ int pv_ro_page_fault(unsigned long addr,
     int rc;
     bool mmio_ro;
 
+    /* Not part of the initializer, for old gcc to cope. */
+    ctxt.cpu_policy = currd->arch.cpu_policy;
+
     /* Attempt to read the PTE that maps the VA being accessed. */
     pte = guest_get_eff_kern_l1e(addr);

On 18/04/2023 11:15 am, Jan Beulich wrote:
> Old gcc won't cope with initializers involving unnamed struct/union
> fields.
>
> Fixes: 441b1b2a50ea ("x86/emul: Switch x86_emulate_ctxt to cpu_policy")
> Signed-off-by: Jan Beulich <jbeulich@suse.com>


Urgh.  Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> I guess, but
I'd honestly far rather delete support for such obsolete compilers.