diff options
author | Marc Zyngier <marc.zyngier@arm.com> | 2017-03-27 17:03:43 +0100 |
---|---|---|
committer | Christoffer Dall <cdall@linaro.org> | 2017-04-09 07:49:15 -0700 |
commit | b6b7a8069d5f44bcc248f5d067cdb22debadfa56 (patch) | |
tree | 7c37c64ac262288485512eabf2b3bd59999eb44f /arch/arm64/kvm | |
parent | e70b952263445ef3f0e4934d7277145f0fecd709 (diff) |
arm64: KVM: Do not corrupt registers on failed 64bit CP read
If we fail to emulate a mrrc instruction, we:
1) deliver an exception,
2) spit a nastygram on the console,
3) write back some garbage to Rt/Rt2
While 1) and 2) are perfectly acceptable, 3) is out of the scope of
the architecture... Let's mimick the code in kvm_handle_cp_32 and
be more cautious.
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Diffstat (limited to 'arch/arm64/kvm')
-rw-r--r-- | arch/arm64/kvm/sys_regs.c | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 2f4418ed4a70..582d68ee4b01 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1678,20 +1678,25 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu, params.regval |= vcpu_get_reg(vcpu, Rt2) << 32; } - if (!emulate_cp(vcpu, ¶ms, target_specific, nr_specific)) - goto out; - if (!emulate_cp(vcpu, ¶ms, global, nr_global)) - goto out; - - unhandled_cp_access(vcpu, ¶ms); + /* + * Try to emulate the coprocessor access using the target + * specific table first, and using the global table afterwards. + * If either of the tables contains a handler, handle the + * potential register operation in the case of a read and return + * with success. + */ + if (!emulate_cp(vcpu, ¶ms, target_specific, nr_specific) || + !emulate_cp(vcpu, ¶ms, global, nr_global)) { + /* Split up the value between registers for the read side */ + if (!params.is_write) { + vcpu_set_reg(vcpu, Rt, lower_32_bits(params.regval)); + vcpu_set_reg(vcpu, Rt2, upper_32_bits(params.regval)); + } -out: - /* Split up the value between registers for the read side */ - if (!params.is_write) { - vcpu_set_reg(vcpu, Rt, lower_32_bits(params.regval)); - vcpu_set_reg(vcpu, Rt2, upper_32_bits(params.regval)); + return 1; } + unhandled_cp_access(vcpu, ¶ms); return 1; } |