Re: [PATCH 41/62] x86/sev-es: Handle MSR events

[Dave Hansen]

On 2/11/20 5:52 AM, Joerg Roedel wrote:
> Implement a handler for #VC exceptions caused by RDMSR/WRMSR
> instructions.

As a general comment on all of these event handlers: Why do we bother
having the hypercalls in the interrupt handler as opposed to just
calling them directly.  What you have is:

	wrmsr()
	-> #VC exception
	   hcall()

But we could make our rd/wrmsr() wrappers just do:

	if (running_on_sev_es())
		hcall(HCALL_MSR_WHATEVER...)
	else
		wrmsr()

and then we don't have any of the nastiness of exception handling.