Commit f9d58956 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Extend unified RESx handling to runtime sanitisation 



Add a new helper to retrieve the RESx values for a given system
register, and use it for the runtime sanitisation.

This results in slightly better code generation for a fairly hot
path in the hypervisor, and additionally covers all sanitised
registers in all conditions, not just the VNCR-based ones.

Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Tested-by: default avatarFuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260202184329.2724080-6-maz@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 08794789

arch/arm64/include/asm/kvm_host.h

+15 −0
Original line number Diff line number Diff line
@@ -635,6 +635,21 @@ struct kvm_sysreg_masks { 
	struct resx mask[NR_SYS_REGS - __SANITISED_REG_START__];

};



static inline struct resx __kvm_get_sysreg_resx(struct kvm_arch *arch,

						enum vcpu_sysreg sr)

{

	struct kvm_sysreg_masks *masks;



	masks = arch->sysreg_masks;

	if (likely(masks &&

		   sr >= __SANITISED_REG_START__ && sr < NR_SYS_REGS))

		return masks->mask[sr - __SANITISED_REG_START__];



	return (struct resx){};

}



#define kvm_get_sysreg_resx(k, sr) __kvm_get_sysreg_resx(&(k)->arch, (sr))



static inline void __kvm_set_sysreg_resx(struct kvm_arch *arch,

					 enum vcpu_sysreg sr, struct resx resx)

{

arch/arm64/kvm/emulate-nested.c

+1 −9
Original line number Diff line number Diff line
@@ -2427,15 +2427,7 @@ static enum trap_behaviour compute_trap_behaviour(struct kvm_vcpu *vcpu, 


static u64 kvm_get_sysreg_res0(struct kvm *kvm, enum vcpu_sysreg sr)

{

	struct kvm_sysreg_masks *masks;



	/* Only handle the VNCR-backed regs for now */

	if (sr < __VNCR_START__)

		return 0;



	masks = kvm->arch.sysreg_masks;



	return masks->mask[sr - __SANITISED_REG_START__].res0;

	return kvm_get_sysreg_resx(kvm, sr).res0;

}



static bool check_fgt_bit(struct kvm_vcpu *vcpu, enum vcpu_sysreg sr,

arch/arm64/kvm/nested.c

+4 −9
Original line number Diff line number Diff line
@@ -1669,16 +1669,11 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) 
u64 kvm_vcpu_apply_reg_masks(const struct kvm_vcpu *vcpu,

			     enum vcpu_sysreg sr, u64 v)

{

	struct kvm_sysreg_masks *masks;



	masks = vcpu->kvm->arch.sysreg_masks;



	if (masks) {

		sr -= __SANITISED_REG_START__;

	struct resx resx;



		v &= ~masks->mask[sr].res0;

		v |= masks->mask[sr].res1;

	}

	resx = kvm_get_sysreg_resx(vcpu->kvm, sr);

	v &= ~resx.res0;

	v |= resx.res1;



	return v;

}