x86/hyperv: fix invalid writes to MSRs during root partition kexec

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hyperv_cleanup resets the hypercall page by setting the MSR to 0. However,
the root partition is not allowed to write to the GPA bits of the MSR.
Instead, it uses the hypercall page provided by the MSR. Similar is the
case with the reference TSC MSR.

Clear only the enable bit instead of zeroing the entire MSR to make
the code valid for root partition too.

Signed-off-by: Anirudh Rayabharam <anrayabh@linux.microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20221027095729.1676394-3-anrayabh@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

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Anirudh Rayabharam 2022-10-27 15:27:29 +05:30 • committed by Wei Liu

parent 4ad1aa5712

commit 2982635a0b

1 changed files with 7 additions and 4 deletions

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arch/x86/hyperv/hv_init.c

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