[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging-4.14] x86/spec-ctrl: Rename retpoline_safe() to retpoline_calculations()
commit 927a168c39accff6ec7ddee0d530bccdad47412a Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Fri May 26 10:35:47 2023 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Thu Aug 3 19:14:19 2023 +0100 x86/spec-ctrl: Rename retpoline_safe() to retpoline_calculations() This is prep work, split out to simply the diff on the following change. * Rename to retpoline_calculations(), and call unconditionally. It is shortly going to synthesise missing enumerations required for guest safety. * For the model check switch statement, store the result in a variable and break rather than returning directly. No functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> (cherry picked from commit 724c0d94ff79b208312d30676392bfdd693403be) --- xen/arch/x86/spec_ctrl.c | 41 ++++++++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 15 deletions(-) diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c index 44fb4c9d45..1ca46ac33d 100644 --- a/xen/arch/x86/spec_ctrl.c +++ b/xen/arch/x86/spec_ctrl.c @@ -589,9 +589,10 @@ static bool __init check_smt_enabled(void) } /* Calculate whether Retpoline is known-safe on this CPU. */ -static bool __init retpoline_safe(void) +static bool __init retpoline_calculations(void) { unsigned int ucode_rev = this_cpu(cpu_sig).rev; + bool safe = false; if ( boot_cpu_data.x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON) ) return true; @@ -629,29 +630,31 @@ static bool __init retpoline_safe(void) case 0x3f: /* Haswell EX/EP */ case 0x45: /* Haswell D */ case 0x46: /* Haswell H */ - return true; + safe = true; + break; /* * Broadwell processors are retpoline-safe after specific microcode * versions. */ case 0x3d: /* Broadwell */ - return ucode_rev >= 0x2a; + safe = ucode_rev >= 0x2a; break; case 0x47: /* Broadwell H */ - return ucode_rev >= 0x1d; + safe = ucode_rev >= 0x1d; break; case 0x4f: /* Broadwell EP/EX */ - return ucode_rev >= 0xb000021; + safe = ucode_rev >= 0xb000021; break; case 0x56: /* Broadwell D */ switch ( boot_cpu_data.x86_mask ) { - case 2: return ucode_rev >= 0x15; - case 3: return ucode_rev >= 0x7000012; - case 4: return ucode_rev >= 0xf000011; - case 5: return ucode_rev >= 0xe000009; + case 2: safe = ucode_rev >= 0x15; break; + case 3: safe = ucode_rev >= 0x7000012; break; + case 4: safe = ucode_rev >= 0xf000011; break; + case 5: safe = ucode_rev >= 0xe000009; break; default: printk("Unrecognised CPU stepping %#x - assuming not reptpoline safe\n", boot_cpu_data.x86_mask); - return false; + safe = false; + break; } break; @@ -665,7 +668,8 @@ static bool __init retpoline_safe(void) case 0x67: /* Cannonlake? */ case 0x8e: /* Kabylake M */ case 0x9e: /* Kabylake D */ - return false; + safe = false; + break; /* * Atom processors before Goldmont Plus/Gemini Lake are retpoline-safe. @@ -684,13 +688,17 @@ static bool __init retpoline_safe(void) case 0x5c: /* Goldmont */ case 0x5f: /* Denverton */ case 0x85: /* Knights Mill */ - return true; + safe = true; + break; default: printk("Unrecognised CPU model %#x - assuming not reptpoline safe\n", boot_cpu_data.x86_model); - return false; + safe = false; + break; } + + return safe; } /* Calculate whether this CPU speculates past #NM */ @@ -1094,7 +1102,7 @@ void __init init_speculation_mitigations(void) { enum ind_thunk thunk = THUNK_DEFAULT; bool has_spec_ctrl, ibrs = false, hw_smt_enabled; - bool cpu_has_bug_taa; + bool cpu_has_bug_taa, retpoline_safe; hw_smt_enabled = check_smt_enabled(); @@ -1123,6 +1131,9 @@ void __init init_speculation_mitigations(void) thunk = THUNK_JMP; } + /* Determine if retpoline is safe on this CPU. */ + retpoline_safe = retpoline_calculations(); + /* * Has the user specified any custom BTI mitigations? If so, follow their * instructions exactly and disable all heuristics. @@ -1144,7 +1155,7 @@ void __init init_speculation_mitigations(void) * On all hardware, we'd like to use retpoline in preference to * IBRS, but only if it is safe on this hardware. */ - if ( retpoline_safe() ) + if ( retpoline_safe ) thunk = THUNK_RETPOLINE; else if ( has_spec_ctrl ) ibrs = true; -- generated by git-patchbot for /home/xen/git/xen.git#staging-4.14
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