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d="scan'208";a="125280891" From: Andrew Cooper To: Xen-devel CC: Andrew Cooper , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Wei Liu Subject: [PATCH 2/8] x86/spec-ctrl: Fold DO_SPEC_CTRL_EXIT_TO_XEN into it's single user Date: Wed, 13 Sep 2023 21:27:52 +0100 Message-ID: <20230913202758.508225-3-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230913202758.508225-1-andrew.cooper3@citrix.com> References: <20230913202758.508225-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @citrix.com) X-ZM-MESSAGEID: 1694636950639100011 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 o= wn is going to be too generic shortly. No functional change. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich --- CC: Jan Beulich CC: Roger Pau Monn=C3=A9 CC: Wei Liu --- xen/arch/x86/include/asm/spec_ctrl_asm.h | 40 ++++++++++-------------- 1 file changed, 16 insertions(+), 24 deletions(-) diff --git a/xen/arch/x86/include/asm/spec_ctrl_asm.h b/xen/arch/x86/includ= e/asm/spec_ctrl_asm.h index 14ec40e8d32f..dd7c5e8bfc79 100644 --- a/xen/arch/x86/include/asm/spec_ctrl_asm.h +++ b/xen/arch/x86/include/asm/spec_ctrl_asm.h @@ -199,27 +199,6 @@ wrmsr .endm =20 -.macro DO_SPEC_CTRL_EXIT_TO_XEN -/* - * Requires %rbx=3Dstack_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 wh= ich - * 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=3Dspec_ctrl, %rsp=3Dregs/cpuinfo @@ -328,11 +307,24 @@ 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 =20 - DO_SPEC_CTRL_EXIT_TO_XEN + /* + * When returning to Xen context, look to see whether SPEC_CTRL shadow= ing + * is in effect, and reload the shadow value. This covers race condit= ions + * which exist with an NMI/MCE/etc hitting late in the return-to-guest + * path. + */ + xor %edx, %edx =20 -.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 =20 #endif /* __ASSEMBLY__ */ --=20 2.30.2