tjh.dev / kernel
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Revert "KVM: arm64: Snapshot all non-zero RES0/RES1 sysreg fields for later checking"

This reverts commits 99101dda29e3186b1356b0dc4dbb835c02c71ac9 and
b80b701d5a67d07f4df4a21e09cb31f6bc1feeca.

Linus reports that the sysreg reserved bit checks in KVM have led to
build failures, arising from commit fdd867fe9b32 ("arm64/sysreg: Add
register fields for ID_AA64DFR1_EL1") giving meaning to fields that were
previously RES0.

Of course, this is a genuine issue, since KVM's sysreg emulation depends
heavily on the definition of reserved fields. But at this point the
build breakage is far more offensive, and the right course of action is
to revert and retry later.

All of these build-time assertions were on by default before
commit 99101dda29e3 ("KVM: arm64: Make build-time check of RES0/RES1
bits optional"), so deliberately revert it all atomically to avoid
introducing further breakage of bisection.

Link: https://lore.kernel.org/all/CAHk-=whCvkhc8BbFOUf1ddOsgSGgEjwoKv77=HEY1UiVCydGqw@mail.gmail.com/
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

authored by

Oliver Upton and committed by
Linus Torvalds 82affc97 277100b3

-139
-11
arch/arm64/kvm/Kconfig
··· 65 65 66 66 If unsure, or not using protected nVHE (pKVM), say N. 67 67 68 - config KVM_ARM64_RES_BITS_PARANOIA 69 - bool "Build-time check of RES0/RES1 bits" 70 - depends on KVM 71 - default n 72 - help 73 - Say Y here to validate that KVM's knowledge of most system 74 - registers' RES0/RES1 bits matches when the rest of the kernel 75 - defines. Expect the build to fail badly if you enable this. 76 - 77 - Just say N. 78 - 79 68 endif # VIRTUALIZATION
-125
arch/arm64/kvm/check-res-bits.h
··· 1 - // SPDX-License-Identifier: GPL-2.0-only 2 - /* 3 - * Copyright (C) 2024 - Google LLC 4 - * Author: Marc Zyngier <maz@kernel.org> 5 - */ 6 - 7 - #include <asm/sysreg-defs.h> 8 - 9 - /* 10 - * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING 11 - * 12 - * If any of these BUILD_BUG_ON() fails, that's because some bits that 13 - * were reserved have gained some other meaning, and KVM needs to know 14 - * about those. 15 - * 16 - * In such case, do *NOT* blindly change the assertion so that it 17 - * passes, but also teach the rest of the code about the actual 18 - * change. 19 - * 20 - * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING 21 - */ 22 - static inline void check_res_bits(void) 23 - { 24 - #ifdef CONFIG_KVM_ARM64_RES_BITS_PARANOIA 25 - 26 - BUILD_BUG_ON(OSDTRRX_EL1_RES0 != (GENMASK_ULL(63, 32))); 27 - BUILD_BUG_ON(MDCCINT_EL1_RES0 != (GENMASK_ULL(63, 31) | GENMASK_ULL(28, 0))); 28 - BUILD_BUG_ON(MDSCR_EL1_RES0 != (GENMASK_ULL(63, 36) | GENMASK_ULL(28, 28) | GENMASK_ULL(25, 24) | GENMASK_ULL(20, 20) | GENMASK_ULL(18, 16) | GENMASK_ULL(11, 7) | GENMASK_ULL(5, 1))); 29 - BUILD_BUG_ON(OSDTRTX_EL1_RES0 != (GENMASK_ULL(63, 32))); 30 - BUILD_BUG_ON(OSECCR_EL1_RES0 != (GENMASK_ULL(63, 32))); 31 - BUILD_BUG_ON(OSLAR_EL1_RES0 != (GENMASK_ULL(63, 1))); 32 - BUILD_BUG_ON(ID_PFR0_EL1_RES0 != (GENMASK_ULL(63, 32))); 33 - BUILD_BUG_ON(ID_PFR1_EL1_RES0 != (GENMASK_ULL(63, 32))); 34 - BUILD_BUG_ON(ID_DFR0_EL1_RES0 != (GENMASK_ULL(63, 32))); 35 - BUILD_BUG_ON(ID_AFR0_EL1_RES0 != (GENMASK_ULL(63, 16))); 36 - BUILD_BUG_ON(ID_MMFR0_EL1_RES0 != (GENMASK_ULL(63, 32))); 37 - BUILD_BUG_ON(ID_MMFR1_EL1_RES0 != (GENMASK_ULL(63, 32))); 38 - BUILD_BUG_ON(ID_MMFR2_EL1_RES0 != (GENMASK_ULL(63, 32))); 39 - BUILD_BUG_ON(ID_MMFR3_EL1_RES0 != (GENMASK_ULL(63, 32))); 40 - BUILD_BUG_ON(ID_ISAR0_EL1_RES0 != (GENMASK_ULL(63, 28))); 41 - BUILD_BUG_ON(ID_ISAR1_EL1_RES0 != (GENMASK_ULL(63, 32))); 42 - BUILD_BUG_ON(ID_ISAR2_EL1_RES0 != (GENMASK_ULL(63, 32))); 43 - BUILD_BUG_ON(ID_ISAR3_EL1_RES0 != (GENMASK_ULL(63, 32))); 44 - BUILD_BUG_ON(ID_ISAR4_EL1_RES0 != (GENMASK_ULL(63, 32))); 45 - BUILD_BUG_ON(ID_ISAR5_EL1_RES0 != (GENMASK_ULL(63, 32) | GENMASK_ULL(23, 20))); 46 - BUILD_BUG_ON(ID_ISAR6_EL1_RES0 != (GENMASK_ULL(63, 28))); 47 - BUILD_BUG_ON(ID_MMFR4_EL1_RES0 != (GENMASK_ULL(63, 32))); 48 - BUILD_BUG_ON(MVFR0_EL1_RES0 != (GENMASK_ULL(63, 32))); 49 - BUILD_BUG_ON(MVFR1_EL1_RES0 != (GENMASK_ULL(63, 32))); 50 - BUILD_BUG_ON(MVFR2_EL1_RES0 != (GENMASK_ULL(63, 8))); 51 - BUILD_BUG_ON(ID_PFR2_EL1_RES0 != (GENMASK_ULL(63, 12))); 52 - BUILD_BUG_ON(ID_DFR1_EL1_RES0 != (GENMASK_ULL(63, 8))); 53 - BUILD_BUG_ON(ID_MMFR5_EL1_RES0 != (GENMASK_ULL(63, 8))); 54 - BUILD_BUG_ON(ID_AA64PFR1_EL1_RES0 != (GENMASK_ULL(23, 20))); 55 - BUILD_BUG_ON(ID_AA64PFR2_EL1_RES0 != (GENMASK_ULL(63, 36) | GENMASK_ULL(31, 12))); 56 - BUILD_BUG_ON(ID_AA64ZFR0_EL1_RES0 != (GENMASK_ULL(63, 60) | GENMASK_ULL(51, 48) | GENMASK_ULL(39, 36) | GENMASK_ULL(31, 28) | GENMASK_ULL(15, 8))); 57 - BUILD_BUG_ON(ID_AA64SMFR0_EL1_RES0 != (GENMASK_ULL(62, 61) | GENMASK_ULL(51, 49) | GENMASK_ULL(31, 31) | GENMASK_ULL(27, 0))); 58 - BUILD_BUG_ON(ID_AA64FPFR0_EL1_RES0 != (GENMASK_ULL(63, 32) | GENMASK_ULL(27, 2))); 59 - BUILD_BUG_ON(ID_AA64DFR0_EL1_RES0 != (GENMASK_ULL(27, 24) | GENMASK_ULL(19, 16))); 60 - BUILD_BUG_ON(ID_AA64DFR1_EL1_RES0 != (GENMASK_ULL(63, 0))); 61 - BUILD_BUG_ON(ID_AA64AFR0_EL1_RES0 != (GENMASK_ULL(63, 32))); 62 - BUILD_BUG_ON(ID_AA64AFR1_EL1_RES0 != (GENMASK_ULL(63, 0))); 63 - BUILD_BUG_ON(ID_AA64ISAR0_EL1_RES0 != (GENMASK_ULL(3, 0))); 64 - BUILD_BUG_ON(ID_AA64ISAR2_EL1_RES0 != (GENMASK_ULL(47, 44))); 65 - BUILD_BUG_ON(ID_AA64ISAR3_EL1_RES0 != (GENMASK_ULL(63, 16))); 66 - BUILD_BUG_ON(ID_AA64MMFR0_EL1_RES0 != (GENMASK_ULL(55, 48))); 67 - BUILD_BUG_ON(ID_AA64MMFR2_EL1_RES0 != (GENMASK_ULL(47, 44))); 68 - BUILD_BUG_ON(ID_AA64MMFR3_EL1_RES0 != (GENMASK_ULL(51, 48))); 69 - BUILD_BUG_ON(ID_AA64MMFR4_EL1_RES0 != (GENMASK_ULL(63, 40) | GENMASK_ULL(35, 28) | GENMASK_ULL(3, 0))); 70 - BUILD_BUG_ON(SCTLR_EL1_RES0 != (GENMASK_ULL(17, 17))); 71 - BUILD_BUG_ON(CPACR_ELx_RES0 != (GENMASK_ULL(63, 30) | GENMASK_ULL(27, 26) | GENMASK_ULL(23, 22) | GENMASK_ULL(19, 18) | GENMASK_ULL(15, 0))); 72 - BUILD_BUG_ON(SMPRI_EL1_RES0 != (GENMASK_ULL(63, 4))); 73 - BUILD_BUG_ON(ZCR_ELx_RES0 != (GENMASK_ULL(63, 9))); 74 - BUILD_BUG_ON(SMCR_ELx_RES0 != (GENMASK_ULL(63, 32) | GENMASK_ULL(29, 9))); 75 - BUILD_BUG_ON(GCSCR_ELx_RES0 != (GENMASK_ULL(63, 10) | GENMASK_ULL(7, 7) | GENMASK_ULL(4, 1))); 76 - BUILD_BUG_ON(GCSPR_ELx_RES0 != (GENMASK_ULL(2, 0))); 77 - BUILD_BUG_ON(GCSCRE0_EL1_RES0 != (GENMASK_ULL(63, 11) | GENMASK_ULL(7, 6) | GENMASK_ULL(4, 1))); 78 - BUILD_BUG_ON(ALLINT_RES0 != (GENMASK_ULL(63, 14) | GENMASK_ULL(12, 0))); 79 - BUILD_BUG_ON(PMSCR_EL1_RES0 != (GENMASK_ULL(63, 8) | GENMASK_ULL(2, 2))); 80 - BUILD_BUG_ON(PMSICR_EL1_RES0 != (GENMASK_ULL(55, 32))); 81 - BUILD_BUG_ON(PMSIRR_EL1_RES0 != (GENMASK_ULL(63, 32) | GENMASK_ULL(7, 1))); 82 - BUILD_BUG_ON(PMSFCR_EL1_RES0 != (GENMASK_ULL(63, 19) | GENMASK_ULL(15, 4))); 83 - BUILD_BUG_ON(PMSLATFR_EL1_RES0 != (GENMASK_ULL(63, 16))); 84 - BUILD_BUG_ON(PMSIDR_EL1_RES0 != (GENMASK_ULL(63, 25) | GENMASK_ULL(7, 7))); 85 - BUILD_BUG_ON(PMBLIMITR_EL1_RES0 != (GENMASK_ULL(11, 6) | GENMASK_ULL(4, 3))); 86 - BUILD_BUG_ON(PMBSR_EL1_RES0 != (GENMASK_ULL(63, 32) | GENMASK_ULL(25, 20))); 87 - BUILD_BUG_ON(PMBIDR_EL1_RES0 != (GENMASK_ULL(63, 12) | GENMASK_ULL(7, 6))); 88 - BUILD_BUG_ON(CONTEXTIDR_ELx_RES0 != (GENMASK_ULL(63, 32))); 89 - BUILD_BUG_ON(CCSIDR_EL1_RES0 != (GENMASK_ULL(63, 32))); 90 - BUILD_BUG_ON(CLIDR_EL1_RES0 != (GENMASK_ULL(63, 47))); 91 - BUILD_BUG_ON(CCSIDR2_EL1_RES0 != (GENMASK_ULL(63, 24))); 92 - BUILD_BUG_ON(GMID_EL1_RES0 != (GENMASK_ULL(63, 4))); 93 - BUILD_BUG_ON(SMIDR_EL1_RES0 != (GENMASK_ULL(63, 32) | GENMASK_ULL(14, 12))); 94 - BUILD_BUG_ON(CSSELR_EL1_RES0 != (GENMASK_ULL(63, 5))); 95 - BUILD_BUG_ON(CTR_EL0_RES0 != (GENMASK_ULL(63, 38) | GENMASK_ULL(30, 30) | GENMASK_ULL(13, 4))); 96 - BUILD_BUG_ON(CTR_EL0_RES1 != (GENMASK_ULL(31, 31))); 97 - BUILD_BUG_ON(DCZID_EL0_RES0 != (GENMASK_ULL(63, 5))); 98 - BUILD_BUG_ON(SVCR_RES0 != (GENMASK_ULL(63, 2))); 99 - BUILD_BUG_ON(FPMR_RES0 != (GENMASK_ULL(63, 38) | GENMASK_ULL(23, 23) | GENMASK_ULL(13, 9))); 100 - BUILD_BUG_ON(HFGxTR_EL2_RES0 != (GENMASK_ULL(51, 51))); 101 - BUILD_BUG_ON(HFGITR_EL2_RES0 != (GENMASK_ULL(63, 63) | GENMASK_ULL(61, 61))); 102 - BUILD_BUG_ON(HDFGRTR_EL2_RES0 != (GENMASK_ULL(49, 49) | GENMASK_ULL(42, 42) | GENMASK_ULL(39, 38) | GENMASK_ULL(21, 20) | GENMASK_ULL(8, 8))); 103 - BUILD_BUG_ON(HDFGWTR_EL2_RES0 != (GENMASK_ULL(63, 63) | GENMASK_ULL(59, 58) | GENMASK_ULL(51, 51) | GENMASK_ULL(47, 47) | GENMASK_ULL(43, 43) | GENMASK_ULL(40, 38) | GENMASK_ULL(34, 34) | GENMASK_ULL(30, 30) | GENMASK_ULL(22, 22) | GENMASK_ULL(9, 9) | GENMASK_ULL(6, 6))); 104 - BUILD_BUG_ON(HAFGRTR_EL2_RES0 != (GENMASK_ULL(63, 50) | GENMASK_ULL(16, 5))); 105 - BUILD_BUG_ON(HCRX_EL2_RES0 != (GENMASK_ULL(63, 25) | GENMASK_ULL(13, 12))); 106 - BUILD_BUG_ON(DACR32_EL2_RES0 != (GENMASK_ULL(63, 32))); 107 - BUILD_BUG_ON(PMSCR_EL2_RES0 != (GENMASK_ULL(63, 8) | GENMASK_ULL(2, 2))); 108 - BUILD_BUG_ON(TCR2_EL1x_RES0 != (GENMASK_ULL(63, 16) | GENMASK_ULL(13, 12) | GENMASK_ULL(9, 6))); 109 - BUILD_BUG_ON(TCR2_EL2_RES0 != (GENMASK_ULL(63, 16))); 110 - BUILD_BUG_ON(LORSA_EL1_RES0 != (GENMASK_ULL(63, 52) | GENMASK_ULL(15, 1))); 111 - BUILD_BUG_ON(LOREA_EL1_RES0 != (GENMASK_ULL(63, 52) | GENMASK_ULL(15, 0))); 112 - BUILD_BUG_ON(LORN_EL1_RES0 != (GENMASK_ULL(63, 8))); 113 - BUILD_BUG_ON(LORC_EL1_RES0 != (GENMASK_ULL(63, 10) | GENMASK_ULL(1, 1))); 114 - BUILD_BUG_ON(LORID_EL1_RES0 != (GENMASK_ULL(63, 24) | GENMASK_ULL(15, 8))); 115 - BUILD_BUG_ON(ISR_EL1_RES0 != (GENMASK_ULL(63, 11) | GENMASK_ULL(5, 0))); 116 - BUILD_BUG_ON(ICC_NMIAR1_EL1_RES0 != (GENMASK_ULL(63, 24))); 117 - BUILD_BUG_ON(TRBLIMITR_EL1_RES0 != (GENMASK_ULL(11, 7))); 118 - BUILD_BUG_ON(TRBBASER_EL1_RES0 != (GENMASK_ULL(11, 0))); 119 - BUILD_BUG_ON(TRBSR_EL1_RES0 != (GENMASK_ULL(63, 56) | GENMASK_ULL(25, 24) | GENMASK_ULL(19, 19) | GENMASK_ULL(16, 16))); 120 - BUILD_BUG_ON(TRBMAR_EL1_RES0 != (GENMASK_ULL(63, 12))); 121 - BUILD_BUG_ON(TRBTRG_EL1_RES0 != (GENMASK_ULL(63, 32))); 122 - BUILD_BUG_ON(TRBIDR_EL1_RES0 != (GENMASK_ULL(63, 12) | GENMASK_ULL(7, 6))); 123 - 124 - #endif 125 - }
-3
arch/arm64/kvm/sys_regs.c
··· 32 32 33 33 #include <trace/events/kvm.h> 34 34 35 - #include "check-res-bits.h" 36 35 #include "sys_regs.h" 37 36 38 37 #include "trace.h" ··· 4108 4109 bool valid = true; 4109 4110 unsigned int i; 4110 4111 int ret = 0; 4111 - 4112 - check_res_bits(); 4113 4112 4114 4113 /* Make sure tables are unique and in order. */ 4115 4114 valid &= check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs), false);