KVM: arm64: Snapshot all non-zero RES0/RES1 sysreg fields for later checking

As KVM now strongly relies on accurately handling the RES0/RES1 bits
on a number of paths, add a compile-time checker that will blow in
the face of the innocent bystander, should they try to sneak in an
update that changes any of these RES0/RES1 fields.

It is expected that such an update will come with the relevant
KVM update if needed.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-26-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

2 files changed, 124 insertions, 0 deletions

diff --git a/arch/arm64/kvm/check-res-bits.h b/arch/arm64/kvm/check-res-bits.h
new file mode 100644
index 000000000000..967b5d171d53
--- /dev/null
+++ b/arch/arm64/kvm/check-res-bits.h
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 - Google LLC
+ * Author: Marc Zyngier <maz@kernel.org>
+ */
+
+#include <asm/sysreg-defs.h>
+
+/*
+ * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+ *
+ * If any of these BUILD_BUG_ON() fails, that's because some bits that
+ * were reserved have gained some other meaning, and KVM needs to know
+ * about those.
+ *
+ * In such case, do *NOT* blindly change the assertion so that it
+ * passes, but also teach the rest of the code about the actual
+ * change.
+ *
+ * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+ */
+static inline void check_res_bits(void)
+{
+	BUILD_BUG_ON(OSDTRRX_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(MDCCINT_EL1_RES0		!= (GENMASK_ULL(63, 31) | GENMASK_ULL(28, 0)));
+	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)));
+	BUILD_BUG_ON(OSDTRTX_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(OSECCR_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(OSLAR_EL1_RES0		!= (GENMASK_ULL(63, 1)));
+	BUILD_BUG_ON(ID_PFR0_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_PFR1_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_DFR0_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_AFR0_EL1_RES0		!= (GENMASK_ULL(63, 16)));
+	BUILD_BUG_ON(ID_MMFR0_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_MMFR1_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_MMFR2_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_MMFR3_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_ISAR0_EL1_RES0		!= (GENMASK_ULL(63, 28)));
+	BUILD_BUG_ON(ID_ISAR1_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_ISAR2_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_ISAR3_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_ISAR4_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_ISAR5_EL1_RES0		!= (GENMASK_ULL(63, 32) | GENMASK_ULL(23, 20)));
+	BUILD_BUG_ON(ID_ISAR6_EL1_RES0		!= (GENMASK_ULL(63, 28)));
+	BUILD_BUG_ON(ID_MMFR4_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(MVFR0_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(MVFR1_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(MVFR2_EL1_RES0		!= (GENMASK_ULL(63, 8)));
+	BUILD_BUG_ON(ID_PFR2_EL1_RES0		!= (GENMASK_ULL(63, 12)));
+	BUILD_BUG_ON(ID_DFR1_EL1_RES0		!= (GENMASK_ULL(63, 8)));
+	BUILD_BUG_ON(ID_MMFR5_EL1_RES0		!= (GENMASK_ULL(63, 8)));
+	BUILD_BUG_ON(ID_AA64PFR1_EL1_RES0	!= (GENMASK_ULL(23, 20)));
+	BUILD_BUG_ON(ID_AA64PFR2_EL1_RES0	!= (GENMASK_ULL(63, 36) | GENMASK_ULL(31, 12)));
+	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)));
+	BUILD_BUG_ON(ID_AA64SMFR0_EL1_RES0	!= (GENMASK_ULL(62, 61) | GENMASK_ULL(51, 49) | GENMASK_ULL(31, 31) | GENMASK_ULL(27, 0)));
+	BUILD_BUG_ON(ID_AA64FPFR0_EL1_RES0	!= (GENMASK_ULL(63, 32) | GENMASK_ULL(27, 2)));
+	BUILD_BUG_ON(ID_AA64DFR0_EL1_RES0	!= (GENMASK_ULL(27, 24) | GENMASK_ULL(19, 16)));
+	BUILD_BUG_ON(ID_AA64DFR1_EL1_RES0	!= (GENMASK_ULL(63, 0)));
+	BUILD_BUG_ON(ID_AA64AFR0_EL1_RES0	!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(ID_AA64AFR1_EL1_RES0	!= (GENMASK_ULL(63, 0)));
+	BUILD_BUG_ON(ID_AA64ISAR0_EL1_RES0	!= (GENMASK_ULL(3, 0)));
+	BUILD_BUG_ON(ID_AA64ISAR2_EL1_RES0	!= (GENMASK_ULL(47, 44)));
+	BUILD_BUG_ON(ID_AA64ISAR3_EL1_RES0	!= (GENMASK_ULL(63, 16)));
+	BUILD_BUG_ON(ID_AA64MMFR0_EL1_RES0	!= (GENMASK_ULL(55, 48)));
+	BUILD_BUG_ON(ID_AA64MMFR2_EL1_RES0	!= (GENMASK_ULL(47, 44)));
+	BUILD_BUG_ON(ID_AA64MMFR3_EL1_RES0	!= (GENMASK_ULL(51, 48)));
+	BUILD_BUG_ON(ID_AA64MMFR4_EL1_RES0	!= (GENMASK_ULL(63, 40) | GENMASK_ULL(35, 28) | GENMASK_ULL(3, 0)));
+	BUILD_BUG_ON(SCTLR_EL1_RES0		!= (GENMASK_ULL(17, 17)));
+	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)));
+	BUILD_BUG_ON(SMPRI_EL1_RES0		!= (GENMASK_ULL(63, 4)));
+	BUILD_BUG_ON(ZCR_ELx_RES0		!= (GENMASK_ULL(63, 9)));
+	BUILD_BUG_ON(SMCR_ELx_RES0		!= (GENMASK_ULL(63, 32) | GENMASK_ULL(29, 9)));
+	BUILD_BUG_ON(GCSCR_ELx_RES0		!= (GENMASK_ULL(63, 10) | GENMASK_ULL(7, 7) | GENMASK_ULL(4, 1)));
+	BUILD_BUG_ON(GCSPR_ELx_RES0		!= (GENMASK_ULL(2, 0)));
+	BUILD_BUG_ON(GCSCRE0_EL1_RES0		!= (GENMASK_ULL(63, 11) | GENMASK_ULL(7, 6) | GENMASK_ULL(4, 1)));
+	BUILD_BUG_ON(ALLINT_RES0		!= (GENMASK_ULL(63, 14) | GENMASK_ULL(12, 0)));
+	BUILD_BUG_ON(PMSCR_EL1_RES0		!= (GENMASK_ULL(63, 8) | GENMASK_ULL(2, 2)));
+	BUILD_BUG_ON(PMSICR_EL1_RES0		!= (GENMASK_ULL(55, 32)));
+	BUILD_BUG_ON(PMSIRR_EL1_RES0		!= (GENMASK_ULL(63, 32) | GENMASK_ULL(7, 1)));
+	BUILD_BUG_ON(PMSFCR_EL1_RES0		!= (GENMASK_ULL(63, 19) | GENMASK_ULL(15, 4)));
+	BUILD_BUG_ON(PMSLATFR_EL1_RES0		!= (GENMASK_ULL(63, 16)));
+	BUILD_BUG_ON(PMSIDR_EL1_RES0		!= (GENMASK_ULL(63, 25) | GENMASK_ULL(7, 7)));
+	BUILD_BUG_ON(PMBLIMITR_EL1_RES0		!= (GENMASK_ULL(11, 6) | GENMASK_ULL(4, 3)));
+	BUILD_BUG_ON(PMBSR_EL1_RES0		!= (GENMASK_ULL(63, 32) | GENMASK_ULL(25, 20)));
+	BUILD_BUG_ON(PMBIDR_EL1_RES0		!= (GENMASK_ULL(63, 12) | GENMASK_ULL(7, 6)));
+	BUILD_BUG_ON(CONTEXTIDR_ELx_RES0	!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(CCSIDR_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(CLIDR_EL1_RES0		!= (GENMASK_ULL(63, 47)));
+	BUILD_BUG_ON(CCSIDR2_EL1_RES0		!= (GENMASK_ULL(63, 24)));
+	BUILD_BUG_ON(GMID_EL1_RES0		!= (GENMASK_ULL(63, 4)));
+	BUILD_BUG_ON(SMIDR_EL1_RES0		!= (GENMASK_ULL(63, 32) | GENMASK_ULL(14, 12)));
+	BUILD_BUG_ON(CSSELR_EL1_RES0		!= (GENMASK_ULL(63, 5)));
+	BUILD_BUG_ON(CTR_EL0_RES0		!= (GENMASK_ULL(63, 38) | GENMASK_ULL(30, 30) | GENMASK_ULL(13, 4)));
+	BUILD_BUG_ON(CTR_EL0_RES1       	!= (GENMASK_ULL(31, 31)));
+	BUILD_BUG_ON(DCZID_EL0_RES0		!= (GENMASK_ULL(63, 5)));
+	BUILD_BUG_ON(SVCR_RES0			!= (GENMASK_ULL(63, 2)));
+	BUILD_BUG_ON(FPMR_RES0			!= (GENMASK_ULL(63, 38) | GENMASK_ULL(23, 23) | GENMASK_ULL(13, 9)));
+	BUILD_BUG_ON(HFGxTR_EL2_RES0		!= (GENMASK_ULL(51, 51)));
+	BUILD_BUG_ON(HFGITR_EL2_RES0		!= (GENMASK_ULL(63, 63) | GENMASK_ULL(61, 61)));
+	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)));
+	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)));
+	BUILD_BUG_ON(HAFGRTR_EL2_RES0		!= (GENMASK_ULL(63, 50) | GENMASK_ULL(16, 5)));
+	BUILD_BUG_ON(HCRX_EL2_RES0		!= (GENMASK_ULL(63, 25) | GENMASK_ULL(13, 12)));
+	BUILD_BUG_ON(DACR32_EL2_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(PMSCR_EL2_RES0		!= (GENMASK_ULL(63, 8) | GENMASK_ULL(2, 2)));
+	BUILD_BUG_ON(TCR2_EL1x_RES0		!= (GENMASK_ULL(63, 16) | GENMASK_ULL(13, 12) | GENMASK_ULL(9, 6)));
+	BUILD_BUG_ON(TCR2_EL2_RES0		!= (GENMASK_ULL(63, 16)));
+	BUILD_BUG_ON(LORSA_EL1_RES0		!= (GENMASK_ULL(63, 52) | GENMASK_ULL(15, 1)));
+	BUILD_BUG_ON(LOREA_EL1_RES0		!= (GENMASK_ULL(63, 52) | GENMASK_ULL(15, 0)));
+	BUILD_BUG_ON(LORN_EL1_RES0		!= (GENMASK_ULL(63, 8)));
+	BUILD_BUG_ON(LORC_EL1_RES0		!= (GENMASK_ULL(63, 10) | GENMASK_ULL(1, 1)));
+	BUILD_BUG_ON(LORID_EL1_RES0		!= (GENMASK_ULL(63, 24) | GENMASK_ULL(15, 8)));
+	BUILD_BUG_ON(ISR_EL1_RES0		!= (GENMASK_ULL(63, 11) | GENMASK_ULL(5, 0)));
+	BUILD_BUG_ON(ICC_NMIAR1_EL1_RES0	!= (GENMASK_ULL(63, 24)));
+	BUILD_BUG_ON(TRBLIMITR_EL1_RES0		!= (GENMASK_ULL(11, 7)));
+	BUILD_BUG_ON(TRBBASER_EL1_RES0		!= (GENMASK_ULL(11, 0)));
+	BUILD_BUG_ON(TRBSR_EL1_RES0		!= (GENMASK_ULL(63, 56) | GENMASK_ULL(25, 24) | GENMASK_ULL(19, 19) | GENMASK_ULL(16, 16)));
+	BUILD_BUG_ON(TRBMAR_EL1_RES0		!= (GENMASK_ULL(63, 12)));
+	BUILD_BUG_ON(TRBTRG_EL1_RES0		!= (GENMASK_ULL(63, 32)));
+	BUILD_BUG_ON(TRBIDR_EL1_RES0		!= (GENMASK_ULL(63, 12) | GENMASK_ULL(7, 6)));
+}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 2cb69efac1dc..b5335e5a6e6e 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -31,6 +31,7 @@
 
 #include <trace/events/kvm.h>
 
+#include "check-res-bits.h"
 #include "sys_regs.h"
 
 #include "trace.h"
@@ -4021,6 +4022,8 @@ int __init kvm_sys_reg_table_init(void)
 	unsigned int i;
 	int ret = 0;
 
+	check_res_bits();
+
 	/* Make sure tables are unique and in order. */
 	valid &= check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs), false);
 	valid &= check_sysreg_table(cp14_regs, ARRAY_SIZE(cp14_regs), true);