KVM: x86: Add a helper to handle filtering of unpermitted XCR0 features

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Add a helper, kvm_get_filtered_xcr0(), to dedup code that needs to account
for XCR0 features that require explicit opt-in on a per-process basis.  In
addition to documenting when KVM should/shouldn't consult
xstate_get_guest_group_perm(), the helper will also allow sanitizing the
filtered XCR0 to avoid enumerating architecturally illegal XCR0 values,
e.g. XTILE_CFG without XTILE_DATA.

No functional changes intended.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Mingwei Zhang <mizhang@google.com>
[sean: rename helper, move to x86.h, massage changelog]
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Tested-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230405004520.421768-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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Aaron Lewis 2023-04-04 17:45:15 -07:00 • committed by Sean Christopherson

parent 7712145073

commit 6be3ae45f5

3 changed files with 15 additions and 4 deletions

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2

arch/x86/kvm/cpuid.c

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arch/x86/kvm/x86.c

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arch/x86/kvm/x86.h

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