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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: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
hifive-unleashed-5.1
Marc Zyngier 2017-03-27 17:03:40 +01:00 committed by Christoffer Dall
parent 9008c235cb
commit 7b5b4df1a7
2 changed files with 9 additions and 18 deletions
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9
arch/arm64/kvm/sys_regs.c
View File

@ -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;

18
arch/arm64/kvm/sys_regs.h
View File

@ -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)