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Commit b1d4cb69 authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall
Browse files

arm: KVM: Make unexpected register accesses inject an undef 



Reads from write-only system registers are generally confined to
EL1 and not propagated to EL2 (that's what the architecture
mantates). In order to be sure that we have a sane behaviour
even in the unlikely event that we have a broken system, we still
handle it in KVM. Same goes for write to RO registers.

In that case, let's inject an undef into the guest.

Reviewed-by: default avatarChristoffer Dall <cdall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent b6b7a806

arch/arm/kvm/coproc.c

+18 −0
Original line number Diff line number Diff line
@@ -40,6 +40,24 @@ 
 * Co-processor emulation

 *****************************************************************************/



static bool write_to_read_only(struct kvm_vcpu *vcpu,

			       const struct coproc_params *params)

{

	WARN_ONCE(1, "CP15 write to read-only register\n");

	print_cp_instr(params);

	kvm_inject_undefined(vcpu);

	return false;

}



static bool read_from_write_only(struct kvm_vcpu *vcpu,

				 const struct coproc_params *params)

{

	WARN_ONCE(1, "CP15 read to write-only register\n");

	print_cp_instr(params);

	kvm_inject_undefined(vcpu);

	return false;

}



/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */

static u32 cache_levels;

arch/arm/kvm/coproc.h

+0 −18
Original line number Diff line number Diff line
@@ -81,24 +81,6 @@ static inline bool read_zero(struct kvm_vcpu *vcpu, 
	return true;

}



static inline bool write_to_read_only(struct kvm_vcpu *vcpu,

				      const struct coproc_params *params)

{

	kvm_debug("CP15 write to read-only register at: %08lx\n",

		  *vcpu_pc(vcpu));

	print_cp_instr(params);

	return false;

}



static inline bool read_from_write_only(struct kvm_vcpu *vcpu,

					const struct coproc_params *params)

{

	kvm_debug("CP15 read to write-only register at: %08lx\n",

		  *vcpu_pc(vcpu));

	print_cp_instr(params);

	return false;

}



/* Reset functions */

static inline void reset_unknown(struct kvm_vcpu *vcpu,

				 const struct coproc_reg *r)