[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 6/8] x86: enable interrupts earlier with XPTI disabled
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 <jbeulich@xxxxxxxx> --- v4: Split off from earlier patch. --- TBD: It is questionable whether having two back-to-back alternatives keyed to the same feature is a good idea. The original patch had them as a single instance each, but the variant here requires fewer (explicit) labels and hence results in overall more readable code. --- a/xen/arch/x86/x86_64/compat/entry.S +++ b/xen/arch/x86/x86_64/compat/entry.S @@ -194,7 +194,7 @@ ENTRY(compat_post_handle_exception) /* 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_KERNEL_SS,8(%rsp) @@ -220,7 +220,7 @@ ENTRY(cstar_enter) mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Lcstar_cr3_okay: ALTERNATIVE_NOP .Lcstar_cr3_start, .Lcstar_cr3_okay, X86_FEATURE_NO_XPTI - 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 @@ -245,7 +245,7 @@ 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 @@ -270,7 +270,7 @@ ENTRY(lstar_enter) mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Llstar_cr3_okay: ALTERNATIVE_NOP .Llstar_cr3_start, .Llstar_cr3_okay, X86_FEATURE_NO_XPTI - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx testb $TF_kernel_mode,VCPU_thread_flags(%rbx) @@ -281,7 +281,7 @@ 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 @@ -310,7 +310,7 @@ GLOBAL(sysenter_eflags_saved) mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Lsyse_cr3_okay: ALTERNATIVE_NOP .Lsyse_cr3_start, .Lsyse_cr3_okay, X86_FEATURE_NO_XPTI - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx cmpb $0,VCPU_sysenter_disables_events(%rbx) @@ -363,7 +363,7 @@ ENTRY(int80_direct_trap) mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx) .Lint80_cr3_okay: ALTERNATIVE_NOP .Lint80_cr3_start, .Lint80_cr3_okay, X86_FEATURE_NO_XPTI - sti + ALTERNATIVE sti, "", X86_FEATURE_NO_XPTI cmpb $0,untrusted_msi(%rip) UNLIKELY_START(ne, msi_check) _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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