[lkml]   [2020]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v5 03/17] x86/acrn: Introduce an API to check if a VM is privileged
On Mon, Oct 19, 2020 at 02:17:49PM +0800, wrote:
> +bool acrn_is_privileged_vm(void)
> +{
> + return cpuid_eax(acrn_cpuid_base() | ACRN_CPUID_FEATURES) &

I asked in the previous review why that acrn_cpuid_base() is used here,
you said that the base might vary. Looking at hypervisor_cpuid_base(),
it searches in the range [0x40000000, 0x40010000] with an 0x100 offset.

So you're saying that ACRN_CPUID_FEATURES is the first leaf beyond the
base. Close?

If so, why isn't the code doing this?

return cpuid_eax(acrn_cpuid_base() + 1)...

and why doesn't it have a comment above it explaining that the base can
change and it needs to be discovered each time?

> +EXPORT_SYMBOL_GPL(acrn_is_privileged_vm);

Also, that acrn_is_privileged_vm() silly helper is used only once and
I don't like the exported symbols pollution we're doing. So make that
function give you the eax of ACRN_CPUID_FEATURES and callers can do
their testing themselves.

When it turns out that code patterns get repeated, you can then
aggregate stuff into a helper.



 \ /
  Last update: 2020-11-02 15:39    [W:0.250 / U:3.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site