target/i386: add support for VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE

Current QEMU can expose waitpkg to guests when it is available. However,
VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE is still not recognized and
masked by QEMU. This can lead to an unexpected situation when a L1
hypervisor wants to expose waitpkg to a L2 guest. The L1 hypervisor can
assume that VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE exists as waitpkg is
available. The L1 hypervisor then can accidentally expose waitpkg to the
L2 guest. This will cause invalid opcode exception in the L2 guest when
it executes waitpkg related instructions.

This patch adds VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE support, and
sets up dependency between the bit and CPUID_7_0_ECX_WAITPKG. QEMU should
not expose waitpkg feature if VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE is
not available to avoid unexpected invalid opcode exception in L2 guests.

Signed-off-by: Ake Koomsin <ake@igel.co.jp>
Message-ID: <20230807093339.32091-2-ake@igel.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2 files changed