RE: [RFC PATCH V4 08/17] x86/hyperv: Initialize cpu and memory for sev-snp enlightened guest

[Michael Kelley (LINUX)]

From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Sunday, April 16, 2023 12:21 AM
> 
> On 4/12/2023 10:39 PM, Michael Kelley (LINUX) wrote:
> >> +	/* Read processor number and memory layout. */
> >> +	processor_count = *(u32 *)__va(EN_SEV_SNP_PROCESSOR_INFO_ADDR);
> >> +	entry = (struct memory_map_entry *)(__va(EN_SEV_SNP_PROCESSOR_INFO_ADDR)
> >> +			+ sizeof(struct memory_map_entry));
> > Why is the first map entry being skipped?
> 
> The first entry is populated with processor count by Hyper-V.

Perhaps add a comment to acknowledge that the behavior
is a bit unexpected:

The 0th entry in the memory layout array contains just a 32-bit
processor count.  Read that value and then skip over the reminder
of the 0th entry.  Start processing memory_map_entry's with array
element 1.

Michael