x86/umip: Fix decoding of register forms of 0F 01 (SGDT and SIDT aliases)

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commit 27b1fd6201 upstream.

Filter out the register forms of 0F 01 when determining whether or not to
emulate in response to a potential UMIP violation #GP, as SGDT and SIDT only
accept memory operands.  The register variants of 0F 01 are used to encode
instructions for things like VMX and SGX, i.e. not checking the Mod field
would cause the kernel to incorrectly emulate on #GP, e.g. due to a CPL
violation on VMLAUNCH.

Fixes: 1e5db22369 ("x86/umip: Add emulation code for UMIP instructions")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Sean Christopherson 2025-08-08 10:23:57 -07:00 • committed by Greg Kroah-Hartman

parent efc947f836

commit 32e5dbaaa9

1 changed files with 11 additions and 0 deletions

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arch/x86/kernel/umip.c

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