[PATCH 0/2] i386: Don't build TDX for 32-bit target

[PATCH 0/2] i386: Don't build TDX for 32-bit target

[Xiaoyao Li]

Build errors of TDX were reported when built on 32-bit host[1][2].
People were agreed to disable TDX on 32-bit build[3].

This series implemnts the agreement that it makes TDX available when
!I386.

[1] https://lore.kernel.org/qemu-devel/20250602173101.1052983-1-clg@redhat.com/
[2] https://lore.kernel.org/qemu-devel/b8171c39-6a92-4078-a59a-a63d7452e1e9@kaod.org/
[3] https://lore.kernel.org/qemu-devel/a838e7cc-968e-4ca4-ba60-bbf201d689aa@redhat.com/

Xiaoyao Li (2):
  i386/Kconfig: Make I386 and X86_64 independant
  i386/tdx: Don't build TDX for 32bit target

 hw/i386/Kconfig     | 12 ++++++------
 target/i386/Kconfig |  1 -
 2 files changed, 6 insertions(+), 7 deletions(-)

-- 
2.43.0

[PATCH 1/2] i386/Kconfig: Make I386 and X86_64 independant

[Xiaoyao Li]

Commit 4921d0a7535b ('i386: switch boards to "default y"') makes
CONIFG_X86_64 select CONFIG_I386, which makes it difficult to define
X86_64 only configs, e.g., for TDX.

Decouple I386 from X86_64.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 hw/i386/Kconfig     | 10 +++++-----
 target/i386/Kconfig |  1 -
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index eb65bda6e071..6fc353930985 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -74,7 +74,7 @@ config PC_ACPI
 config I440FX
     bool
     default y
-    depends on I386
+    depends on (I386 || X86_64)
     imply E1000_PCI
     imply VMPORT
     imply VMMOUSE
@@ -91,7 +91,7 @@ config I440FX
 config ISAPC
     bool
     default y
-    depends on I386
+    depends on (I386 || X86_64)
     imply VGA_ISA
     select ISA_BUS
     select PC
@@ -103,7 +103,7 @@ config ISAPC
 config Q35
     bool
     default y
-    depends on I386
+    depends on (I386 || X86_64)
     imply VTD
     imply AMD_IOMMU
     imply E1000E_PCI_EXPRESS
@@ -122,7 +122,7 @@ config Q35
 config MICROVM
     bool
     default y
-    depends on I386 && FDT
+    depends on (I386 || X86_64) && FDT
     select DEVICE_TREE
     select SERIAL_ISA # for serial_hds_isa_init()
     select ISA_BUS
@@ -168,4 +168,4 @@ config VMMOUSE
 config XEN_EMU
     bool
     default y
-    depends on KVM && I386
+    depends on KVM && (I386 || X86_64)
diff --git a/target/i386/Kconfig b/target/i386/Kconfig
index 6b0feef02997..f16efa7137d5 100644
--- a/target/i386/Kconfig
+++ b/target/i386/Kconfig
@@ -6,4 +6,3 @@ config I386
 
 config X86_64
     bool
-    select I386
-- 
2.43.0

[PATCH 2/2] i386/tdx: Don't build TDX for 32bit target

[Xiaoyao Li]

TDX cannot work on 32-bit host. It's also not worth supported TDX with
32-bit QEMU.

Thus, make TDX depends on !I386.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 hw/i386/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index 6fc353930985..c58802462a45 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -13,7 +13,7 @@ config SGX
 config TDX
     bool
     select X86_FW_OVMF
-    depends on KVM
+    depends on KVM && !I386
 
 config PC
     bool
-- 
2.43.0

Re: [PATCH 2/2] i386/tdx: Don't build TDX for 32bit target

[Cédric Le Goater]

On 6/25/25 05:49, Xiaoyao Li wrote:
> TDX cannot work on 32-bit host. It's also not worth supported TDX with
> 32-bit QEMU.
> 
> Thus, make TDX depends on !I386.
> 
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
>   hw/i386/Kconfig | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
> index 6fc353930985..c58802462a45 100644
> --- a/hw/i386/Kconfig
> +++ b/hw/i386/Kconfig
> @@ -13,7 +13,7 @@ config SGX
>   config TDX
>       bool
>       select X86_FW_OVMF
> -    depends on KVM
> +    depends on KVM && !I386
>   
>   config PC
>       bool

Both patches look OK.

Out of curiosity, would the change below work as well (without patch 1) ?

Thanks,

C.




@@ -13,7 +13,7 @@ config SGX
  config TDX
      bool
      select X86_FW_OVMF
-    depends on KVM
+    depends on KVM && X86_64
  
  config PC
      bool

Re: [PATCH 2/2] i386/tdx: Don't build TDX for 32bit target

[Xiaoyao Li]

On 6/25/2025 1:59 PM, Cédric Le Goater wrote:
> On 6/25/25 05:49, Xiaoyao Li wrote:
>> TDX cannot work on 32-bit host. It's also not worth supported TDX with
>> 32-bit QEMU.
>>
>> Thus, make TDX depends on !I386.
>>
>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>> ---
>>   hw/i386/Kconfig | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
>> index 6fc353930985..c58802462a45 100644
>> --- a/hw/i386/Kconfig
>> +++ b/hw/i386/Kconfig
>> @@ -13,7 +13,7 @@ config SGX
>>   config TDX
>>       bool
>>       select X86_FW_OVMF
>> -    depends on KVM
>> +    depends on KVM && !I386
>>   config PC
>>       bool
> 
> Both patches look OK.
> 
> Out of curiosity, would the change below work as well (without patch 1) ?
> 
> Thanks,
> 
> C.
> 
> 
> 
> 
> @@ -13,7 +13,7 @@ config SGX
>   config TDX
>       bool
>       select X86_FW_OVMF
> -    depends on KVM
> +    depends on KVM && X86_64
> 
>   config PC
>       bool
> 

It works! (It turns out I'm not clever enough)

Let's leave it to Paolo to pick.

Re: [PATCH 2/2] i386/tdx: Don't build TDX for 32bit target

[Cédric Le Goater]

On 6/25/25 08:36, Xiaoyao Li wrote:
> On 6/25/2025 1:59 PM, Cédric Le Goater wrote:
>> On 6/25/25 05:49, Xiaoyao Li wrote:
>>> TDX cannot work on 32-bit host. It's also not worth supported TDX with
>>> 32-bit QEMU.
>>>
>>> Thus, make TDX depends on !I386.
>>>
>>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>>> ---
>>>   hw/i386/Kconfig | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
>>> index 6fc353930985..c58802462a45 100644
>>> --- a/hw/i386/Kconfig
>>> +++ b/hw/i386/Kconfig
>>> @@ -13,7 +13,7 @@ config SGX
>>>   config TDX
>>>       bool
>>>       select X86_FW_OVMF
>>> -    depends on KVM
>>> +    depends on KVM && !I386
>>>   config PC
>>>       bool
>>
>> Both patches look OK.
>>
>> Out of curiosity, would the change below work as well (without patch 1) ?
>>
>> Thanks,
>>
>> C.
>>
>>
>>
>>
>> @@ -13,7 +13,7 @@ config SGX
>>   config TDX
>>       bool
>>       select X86_FW_OVMF
>> -    depends on KVM
>> +    depends on KVM && X86_64
>>
>>   config PC
>>       bool
>>
> 
> It works! (It turns out I'm not clever enough)
>
> Let's leave it to Paolo to pick.

Could you please resend a v2 so someone can merge it while Paolo is on PTO ?

Thanks,

C.