[RFC PATCH] target/i386: restrict SEV to 64 bit host builds

["Alex Bennée" <alex.bennee@linaro.org>]

Re-enabling the 32 bit host build on i686 showed the recently merged
SEV code doesn't take enough care over its types. While the format
strings could use more portable types there isn't much we can do about
casting uint64_t into a pointer. The easiest solution seems to be just
to disable SEV for a 32 bit build. It's highly unlikely anyone would
want this functionality anyway.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 target/i386/sev.h       | 2 +-
 target/i386/meson.build | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/i386/sev.h b/target/i386/sev.h
index 858005a119..b0cb9dd7ed 100644
--- a/target/i386/sev.h
+++ b/target/i386/sev.h
@@ -45,7 +45,7 @@ typedef struct SevKernelLoaderContext {
     size_t cmdline_size;
 } SevKernelLoaderContext;
 
-#ifdef CONFIG_SEV
+#if defined(CONFIG_SEV) && defined(HOST_X86_64)
 bool sev_enabled(void);
 bool sev_es_enabled(void);
 bool sev_snp_enabled(void);
diff --git a/target/i386/meson.build b/target/i386/meson.build
index 075117989b..d2a008926c 100644
--- a/target/i386/meson.build
+++ b/target/i386/meson.build
@@ -6,7 +6,7 @@ i386_ss.add(files(
   'xsave_helper.c',
   'cpu-dump.c',
 ))
-i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c', 'confidential-guest.c'))
+i386_ss.add(when: ['CONFIG_SEV', 'HOST_X86_64'], if_true: files('host-cpu.c', 'confidential-guest.c'))
 
 # x86 cpu type
 i386_ss.add(when: 'CONFIG_KVM', if_true: files('host-cpu.c'))
@@ -21,7 +21,7 @@ i386_system_ss.add(files(
   'cpu-apic.c',
   'cpu-sysemu.c',
 ))
-i386_system_ss.add(when: 'CONFIG_SEV', if_true: files('sev.c'), if_false: files('sev-sysemu-stub.c'))
+i386_system_ss.add(when: ['CONFIG_SEV', 'HOST_X86_64'], if_true: files('sev.c'), if_false: files('sev-sysemu-stub.c'))
 
 i386_user_ss = ss.source_set()
 
-- 
2.39.2