The STI instances were moved (or added in the INT80 case) to meet TLB flush requirements. When XPTI is disabled, they can be put back where they were (or omitted in the INT80 case).
Signed-off-by: Jan Beulich <[email protected]> Tested-by: Juergen Gross <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Reviewed-by: Wei Liu <[email protected]> --- v5: Re-base. v4: Split off from earlier patch. --- a/xen/arch/x86/x86_64/compat/entry.S +++ b/xen/arch/x86/x86_64/compat/entry.S @@ -200,7 +200,7 @@ ENTRY(cr4_pv32_restore) /* See lstar_enter for entry register state. */ ENTRY(cstar_enter) - /* sti could live here when we don't switch page tables below. */ + ALTERNATIVE nop, sti, X86_FEATURE_NO_XPTI CR4_PV32_RESTORE movq 8(%rsp),%rax /* Restore %rax. */ movq $FLAT_USER_SS32, 8(%rsp) /* Assume a 64bit domain. Compat handled lower. */ @@ -223,7 +223,7 @@ ENTRY(cstar_enter) /* %r12 is still zero at this point. */ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Lcstar_cr3_okay: - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx movq VCPU_domain(%rbx),%rcx --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -247,7 +247,7 @@ UNLIKELY_END(exit_cr3) * %ss must be saved into the space left by the trampoline. */ ENTRY(lstar_enter) - /* sti could live here when we don't switch page tables below. */ + ALTERNATIVE nop, sti, X86_FEATURE_NO_XPTI movq 8(%rsp),%rax /* Restore %rax. */ movq $FLAT_KERNEL_SS,8(%rsp) pushq %r11 @@ -269,7 +269,7 @@ ENTRY(lstar_enter) /* %r12 is still zero at this point. */ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Llstar_cr3_okay: - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx testb $TF_kernel_mode,VCPU_thread_flags(%rbx) @@ -280,7 +280,7 @@ ENTRY(lstar_enter) jmp test_all_events ENTRY(sysenter_entry) - /* sti could live here when we don't switch page tables below. */ + ALTERNATIVE nop, sti, X86_FEATURE_NO_XPTI pushq $FLAT_USER_SS pushq $0 pushfq @@ -306,7 +306,7 @@ GLOBAL(sysenter_eflags_saved) /* %r12 is still zero at this point. */ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Lsyse_cr3_okay: - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx cmpb $0,VCPU_sysenter_disables_events(%rbx) @@ -356,7 +356,7 @@ ENTRY(int80_direct_trap) /* %r12 is still zero at this point. */ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Lint80_cr3_okay: - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI cmpb $0,untrusted_msi(%rip) UNLIKELY_START(ne, msi_check) _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
