The User-Mode Instruction Prevention feature present in recent Intel processor prevents a group of instructions (sgdt, sidt, sldt, smsw, and str) from being executed with CPL > 0. Otherwise, a general protection fault is issued. Add support for UMIP in virtual machines, and also allow emulation of UMIP on older processors by enabling descriptor-table vmexits. This emulation is not perfect, because SMSW cannot be trapped. However, this is not an issue in practice because Linux is _also_ emulating SMSW instructions on behalf of the program that executes them, because some 16-bit programs expect to use SMSW to detect vm86 mode. Paolo Paolo Bonzini (5): KVM: vmx: use X86_CR4_UMIP and X86_FEATURE_UMIP KVM: x86: add support for UMIP KVM: x86: emulate sldt and str KVM: x86: add support for emulating UMIP KVM: vmx: add support for emulating UMIP arch/x86/include/asm/kvm_host.h | 3 ++- arch/x86/kvm/cpuid.c | 6 ++++-- arch/x86/kvm/emulate.c | 40 ++++++++++++++++++++++++++++++++++------ arch/x86/kvm/svm.c | 6 ++++++ arch/x86/kvm/vmx.c | 36 +++++++++++++++++++++++++++++++++--- arch/x86/kvm/x86.c | 3 +++ 6 files changed, 82 insertions(+), 12 deletions(-) -- 1.8.3.1
