Re: [PATCH v6 13/60] i386/tdx: Validate TD attributes

Xiaoyao Li
2024-11-05T11:54:06Z

On 11/5/2024 6:36 PM, Daniel P. Berrangé wrote:
> On Tue, Nov 05, 2024 at 01:23:21AM -0500, Xiaoyao Li wrote:
>> Validate TD attributes with tdx_caps that fixed-0 bits must be zero and
>> fixed-1 bits must be set.
>>
>> Besides, sanity check the attribute bits that have not been supported by
>> QEMU yet. e.g., debug bit, it will be allowed in the future when debug
>> TD support lands in QEMU.
>>
>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
>>
>> ---
>> Changes in v3:
>> - using error_setg() for error report; (Daniel)
>> ---
>> target/i386/kvm/tdx.c | 28 ++++++++++++++++++++++++++--
>> 1 file changed, 26 insertions(+), 2 deletions(-)
>>
>> diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
>> index 6cf81f788fe0..5a9ce2ada89d 100644
>> --- a/target/i386/kvm/tdx.c
>> +++ b/target/i386/kvm/tdx.c
>> @@ -20,6 +20,7 @@
>> #include "kvm_i386.h"
>> #include "tdx.h"
>>
>> +#define TDX_TD_ATTRIBUTES_DEBUG BIT_ULL(0)
>> #define TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE BIT_ULL(28)
>> #define TDX_TD_ATTRIBUTES_PKS BIT_ULL(30)
>> #define TDX_TD_ATTRIBUTES_PERFMON BIT_ULL(63)
>> @@ -141,13 +142,33 @@ static int tdx_kvm_type(X86ConfidentialGuest *cg)
>> return KVM_X86_TDX_VM;
>> }
>>
>> -static void setup_td_guest_attributes(X86CPU *x86cpu)
>> +static int tdx_validate_attributes(TdxGuest *tdx, Error **errp)
>> +{
>> + if ((tdx->attributes & ~tdx_caps->supported_attrs)) {
>> + error_setg(errp, "Invalid attributes 0x%lx for TDX VM "
>> + "(supported: 0x%llx)",
>> + tdx->attributes, tdx_caps->supported_attrs);
>> + return -1;
>
> Minor whitespace accident, with indentation too deep.

Good catch!

btw, how did you catch it? any tool like checkpatch.pl or just by your eyes?

>> + }
>> +
>> + if (tdx->attributes & TDX_TD_ATTRIBUTES_DEBUG) {
>> + error_setg(errp, "Current QEMU doesn't support attributes.debug[bit 0] "
>> + "for TDX VM");
>> + return -1;
>> + }
>> +
>> + return 0;
>> +}
>
> With regards,
> Daniel