Re: [PATCH v4 10/15] x86/xen/msr: Remove calling native_{read,write}_msr{,_safe}() in pmu_msr_{read,write}()

* Xin Li (Intel) [off-list ref] wrote:

hpa found that pmu_msr_write() is actually a completely pointless
function [1]: all it does is shuffle some arguments, then calls
pmu_msr_chk_emulated() and if it returns true AND the emulated flag
is clear then does *exactly the same thing* that the calling code
would have done if pmu_msr_write() itself had returned true.  And
pmu_msr_read() does the equivalent stupidity.

Remove the calls to native_{read,write}_msr{,_safe}() within
pmu_msr_{read,write}().  Instead reuse the existing calling code
that decides whether to call native_{read,write}_msr{,_safe}() based
on the return value from pmu_msr_{read,write}().  Consequently,
eliminate the need to pass an error pointer to pmu_msr_{read,write}().

While at it, refactor pmu_msr_write() to take the MSR value as a u64
argument, replacing the current dual u32 arguments, because the dual
u32 arguments were only used to call native_write_msr{,_safe}(), which
has now been removed.

[1]: https://lore.kernel.org/lkml/0ec48b84-d158-47c6-b14c-3563fd14bcc4@zytor.com/ (local)

Suggested-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Sign-off-by: Xin Li (Intel) [off-list ref]

'Sign-off-by' is not a proper SOB tag, I've changed it to Signed-off-by.

Thanks,

	Ingo