Messages in this thread |  | | Date | Fri, 2 Dec 2022 09:06:04 -0800 | Subject | Re: [PATCH v7 09/20] x86/virt/tdx: Get information about TDX module and TDX-capable memory | From | Dave Hansen <> |
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On 12/2/22 03:11, Huang, Kai wrote: > And also to address you concern that not all 892 bytes are reserved, how about > below: > > union { > - struct cpuid_config cpuid_configs[0]; > - u8 reserved5[892]; > + DECLARE_FLEX_ARRAY(struct cpuid_config, cpuid_configs); > + u8 padding[892]; > }; > } __packed __aligned(TDSYSINFO_STRUCT_ALIGNMENT); > > The goal is to make the size of 'struct tdsysinfo_struct' to be 1024B so we can > use a static variable for it, and at the meantime, it can still have 1024B > (enough space) for the TDH.SYS.INFO to write to.
I just don't like the open-coded sizes.
For instance, wouldn't it be great if you didn't have to know the size of *ANYTHING* else to properly size the '892'?
Maybe we just need some helpers to hide the gunk:
#define DECLARE_PADDED_STRUCT(type, name, alignment) \ struct type##_padded { \ union { \ struct type name; \ u8 padding[alignment]; \ } \ } name##_padded;
#define PADDED_STRUCT(name) (name##_padded.name)
That can get used like this:
DECLARE_PADDED_STRUCT(struct tdsysinfo_struct, tdsysinfo, TDSYSINFO_STRUCT_ALIGNMENT);
struct tdsysinfo_struct sysinfo = PADDED_STRUCT(tdsysinfo)
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