Commit 99101dda authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

KVM: arm64: Make build-time check of RES0/RES1 bits optional 



In order to ease the transition towards a state of absolute
paranoia where all RES0/RES1 bits gets checked against what
KVM know of them, make the checks optional and guarded by a
config symbol (CONFIG_KVM_ARM64_RES_BITS_PARANOIA) default to n.

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/kvm/87frxka7ud.wl-maz@kernel.org/


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 89176658

arch/arm64/kvm/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -67,4 +67,15 @@ config PROTECTED_NVHE_STACKTRACE 


	  If unsure, or not using protected nVHE (pKVM), say N.



config KVM_ARM64_RES_BITS_PARANOIA

	bool "Build-time check of RES0/RES1 bits"

	depends on KVM

	default n

	help

	  Say Y here to validate that KVM's knowledge of most system

	  registers' RES0/RES1 bits matches when the rest of the kernel

	  defines. Expect the build to fail badly if you enable this.



	  Just say N.



endif # VIRTUALIZATION

arch/arm64/kvm/check-res-bits.h

+4 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
 */

static inline void check_res_bits(void)

{

#ifdef CONFIG_KVM_ARM64_RES_BITS_PARANOIA



	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)));
@@ -118,4 +120,6 @@ static inline void check_res_bits(void) 
	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)));



#endif

}