x86/hyperv: add noop functions to x86_init mpparse functions

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[ Upstream commit 9e2d0c3365 ]

Hyper-V can run VMs at different privilege "levels" known as Virtual
Trust Levels (VTL). Sometimes, it chooses to run two different VMs
at different levels but they share some of their address space. In
such setups VTL2 (higher level VM) has visibility of all of the
VTL0 (level 0) memory space.

When the CONFIG_X86_MPPARSE is enabled for VTL2, the VTL2 kernel
performs a search within the low memory to locate MP tables. However,
in systems where VTL0 manages the low memory and may contain valid
tables, this scanning can result in incorrect MP table information
being provided to the VTL2 kernel, mistakenly considering VTL0's MP
table as its own

Add noop functions to avoid MP parse scan by VTL2.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/1687537688-5397-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Saurabh Sengar 2023-06-23 09:28:08 -07:00 • committed by Greg Kroah-Hartman

parent ee66ee99ee

commit 6e2e2bf0ea

1 changed files with 4 additions and 0 deletions

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arch/x86/hyperv/hv_vtl.c

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