From: Andrew Cooper Date: Tue, 17 Apr 2018 13:15:04 +0000 (+0100) Subject: x86/spec_ctrl: Split X86_FEATURE_SC_MSR into PV and HVM variants X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~98 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=fa9eb09d446a1279f5e861e6b84fa8675dabf148;p=xen.git x86/spec_ctrl: Split X86_FEATURE_SC_MSR into PV and HVM variants In order to separately control whether MSR_SPEC_CTRL is virtualised for PV and HVM guests, split the feature used to control runtime alternatives into two. Xen will use MSR_SPEC_CTRL itself if either of these features are active. Signed-off-by: Andrew Cooper Reviewed-by: Wei Liu Reviewed-by: Jan Beulich Release-acked-by: Juergen Gross --- diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c index c7ec9a34d5..0978e1c1ac 100644 --- a/xen/arch/x86/spec_ctrl.c +++ b/xen/arch/x86/spec_ctrl.c @@ -128,7 +128,8 @@ static void __init print_details(enum ind_thunk thunk, uint64_t caps) thunk == THUNK_RETPOLINE ? "RETPOLINE" : thunk == THUNK_LFENCE ? "LFENCE" : thunk == THUNK_JMP ? "JMP" : "?", - boot_cpu_has(X86_FEATURE_SC_MSR) ? + (boot_cpu_has(X86_FEATURE_SC_MSR_PV) || + boot_cpu_has(X86_FEATURE_SC_MSR_HVM)) ? default_xen_spec_ctrl & SPEC_CTRL_IBRS ? " IBRS+" : " IBRS-" : "", opt_ibpb ? " IBPB" : "", @@ -367,7 +368,8 @@ void __init init_speculation_mitigations(void) * need the IBRS entry/exit logic to virtualise IBRS support for * guests. */ - setup_force_cpu_cap(X86_FEATURE_SC_MSR); + setup_force_cpu_cap(X86_FEATURE_SC_MSR_PV); + setup_force_cpu_cap(X86_FEATURE_SC_MSR_HVM); if ( ibrs ) default_xen_spec_ctrl |= SPEC_CTRL_IBRS; diff --git a/xen/include/asm-x86/cpufeatures.h b/xen/include/asm-x86/cpufeatures.h index 32b7f0457e..b90aa2d046 100644 --- a/xen/include/asm-x86/cpufeatures.h +++ b/xen/include/asm-x86/cpufeatures.h @@ -26,8 +26,9 @@ XEN_CPUFEATURE(LFENCE_DISPATCH, (FSCAPINTS+0)*32+12) /* lfence set as Dispatch S XEN_CPUFEATURE(IND_THUNK_LFENCE,(FSCAPINTS+0)*32+13) /* Use IND_THUNK_LFENCE */ XEN_CPUFEATURE(IND_THUNK_JMP, (FSCAPINTS+0)*32+14) /* Use IND_THUNK_JMP */ XEN_CPUFEATURE(XEN_IBPB, (FSCAPINTS+0)*32+15) /* IBRSB || IBPB */ -XEN_CPUFEATURE(SC_MSR, (FSCAPINTS+0)*32+16) /* MSR_SPEC_CTRL used by Xen */ +XEN_CPUFEATURE(SC_MSR_PV, (FSCAPINTS+0)*32+16) /* MSR_SPEC_CTRL used by Xen for PV */ +XEN_CPUFEATURE(SC_MSR_HVM, (FSCAPINTS+0)*32+17) /* MSR_SPEC_CTRL used by Xen for HVM */ XEN_CPUFEATURE(SC_RSB_PV, (FSCAPINTS+0)*32+18) /* RSB overwrite needed for PV */ XEN_CPUFEATURE(SC_RSB_HVM, (FSCAPINTS+0)*32+19) /* RSB overwrite needed for HVM */ XEN_CPUFEATURE(NO_XPTI, (FSCAPINTS+0)*32+20) /* XPTI mitigation not in use */ -XEN_CPUFEATURE(SC_MSR_IDLE, (FSCAPINTS+0)*32+21) /* SC_MSR && default_xen_spec_ctrl */ +XEN_CPUFEATURE(SC_MSR_IDLE, (FSCAPINTS+0)*32+21) /* (SC_MSR_PV || SC_MSR_HVM) && default_xen_spec_ctrl */ diff --git a/xen/include/asm-x86/spec_ctrl_asm.h b/xen/include/asm-x86/spec_ctrl_asm.h index bf36b5a886..edace2a04e 100644 --- a/xen/include/asm-x86/spec_ctrl_asm.h +++ b/xen/include/asm-x86/spec_ctrl_asm.h @@ -223,34 +223,34 @@ #define SPEC_CTRL_ENTRY_FROM_HVM \ ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_HVM; \ ALTERNATIVE "", DO_SPEC_CTRL_ENTRY_FROM_HVM, \ - X86_FEATURE_SC_MSR + X86_FEATURE_SC_MSR_HVM /* Use after an entry from PV context (syscall/sysenter/int80/int82/etc). */ #define SPEC_CTRL_ENTRY_FROM_PV \ ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV; \ ALTERNATIVE "", __stringify(DO_SPEC_CTRL_ENTRY maybexen=0), \ - X86_FEATURE_SC_MSR + X86_FEATURE_SC_MSR_PV /* Use in interrupt/exception context. May interrupt Xen or PV context. */ #define SPEC_CTRL_ENTRY_FROM_INTR \ ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV; \ ALTERNATIVE "", __stringify(DO_SPEC_CTRL_ENTRY maybexen=1), \ - X86_FEATURE_SC_MSR + X86_FEATURE_SC_MSR_PV /* Use when exiting to Xen context. */ #define SPEC_CTRL_EXIT_TO_XEN \ ALTERNATIVE "", \ - DO_SPEC_CTRL_EXIT_TO_XEN, X86_FEATURE_SC_MSR + DO_SPEC_CTRL_EXIT_TO_XEN, X86_FEATURE_SC_MSR_PV /* Use when exiting to PV guest context. */ #define SPEC_CTRL_EXIT_TO_PV \ ALTERNATIVE "", \ - DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR + DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR_PV /* Use when exiting to HVM guest context. */ #define SPEC_CTRL_EXIT_TO_HVM \ ALTERNATIVE "", \ - DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR + DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR_HVM /* * Use in IST interrupt/exception context. May interrupt Xen or PV context.