Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7b5b4df1 authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall
Browse files

arm64: KVM: Make unexpected reads from WO registers 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.

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

Let's also remove write_to_read_only which isn't used anywhere.

Reviewed-by: default avatarChristoffer Dall <cdall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 9008c235

arch/arm64/kvm/sys_regs.c

+9 −0
Original line number Diff line number Diff line
@@ -55,6 +55,15 @@ 
 * 64bit interface.

 */



static bool read_from_write_only(struct kvm_vcpu *vcpu,

				 const struct sys_reg_params *params)

{

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

	print_sys_reg_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/arm64/kvm/sys_regs.h

+0 −18
Original line number Diff line number Diff line
@@ -83,24 +83,6 @@ static inline bool read_zero(struct kvm_vcpu *vcpu, 
	return true;

}



static inline bool write_to_read_only(struct kvm_vcpu *vcpu,

				      const struct sys_reg_params *params)

{

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

		  *vcpu_pc(vcpu));

	print_sys_reg_instr(params);

	return false;

}



static inline bool read_from_write_only(struct kvm_vcpu *vcpu,

					const struct sys_reg_params *params)

{

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

		  *vcpu_pc(vcpu));

	print_sys_reg_instr(params);

	return false;

}



/* Reset functions */

static inline void reset_unknown(struct kvm_vcpu *vcpu,

				 const struct sys_reg_desc *r)