[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.15] x86/spec-ctrl: Fold DO_SPEC_CTRL_EXIT_TO_XEN into it's single user
commit 806893afb66fe7fa96ec495f2b7561bb396053ee Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Tue Sep 12 17:03:16 2023 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Tue Sep 19 19:38:35 2023 +0100 x86/spec-ctrl: Fold DO_SPEC_CTRL_EXIT_TO_XEN into it's single user With the SPEC_CTRL_EXIT_TO_XEN{,_IST} confusion fixed, it's now obvious that there's only a single EXIT_TO_XEN path. Fold DO_SPEC_CTRL_EXIT_TO_XEN into SPEC_CTRL_EXIT_TO_XEN to simplify further fixes. When merging labels, switch the name to .L\@_skip_sc_msr as "skip" on its own is going to be too generic shortly. No functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> (cherry picked from commit 694bb0f280fd08a4377e36e32b84b5062def4de2) --- xen/include/asm-x86/spec_ctrl_asm.h | 40 +++++++++++++++---------------------- 1 file changed, 16 insertions(+), 24 deletions(-) diff --git a/xen/include/asm-x86/spec_ctrl_asm.h b/xen/include/asm-x86/spec_ctrl_asm.h index 253e633f44..bff3e7f085 100644 --- a/xen/include/asm-x86/spec_ctrl_asm.h +++ b/xen/include/asm-x86/spec_ctrl_asm.h @@ -211,27 +211,6 @@ wrmsr .endm -.macro DO_SPEC_CTRL_EXIT_TO_XEN -/* - * Requires %rbx=stack_end - * Clobbers %rax, %rcx, %rdx - * - * When returning to Xen context, look to see whether SPEC_CTRL shadowing is - * in effect, and reload the shadow value. This covers race conditions which - * exist with an NMI/MCE/etc hitting late in the return-to-guest path. - */ - xor %edx, %edx - - testb $SCF_use_shadow, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%rbx) - jz .L\@_skip - - mov STACK_CPUINFO_FIELD(shadow_spec_ctrl)(%rbx), %eax - mov $MSR_SPEC_CTRL, %ecx - wrmsr - -.L\@_skip: -.endm - .macro DO_SPEC_CTRL_EXIT_TO_GUEST /* * Requires %eax=spec_ctrl, %rsp=regs/cpuinfo @@ -340,11 +319,24 @@ UNLIKELY_DISPATCH_LABEL(\@_serialise): * Clobbers %rax, %rcx, %rdx */ testb $SCF_ist_sc_msr, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%rbx) - jz .L\@_skip + jz .L\@_skip_sc_msr - DO_SPEC_CTRL_EXIT_TO_XEN + /* + * When returning to Xen context, look to see whether SPEC_CTRL shadowing + * is in effect, and reload the shadow value. This covers race conditions + * which exist with an NMI/MCE/etc hitting late in the return-to-guest + * path. + */ + xor %edx, %edx -.L\@_skip: + testb $SCF_use_shadow, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%rbx) + jz .L\@_skip_sc_msr + + mov STACK_CPUINFO_FIELD(shadow_spec_ctrl)(%rbx), %eax + mov $MSR_SPEC_CTRL, %ecx + wrmsr + +.L\@_skip_sc_msr: .endm #endif /* __ASSEMBLY__ */ -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.15
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