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authorMarc Zyngier <marc.zyngier@arm.com>2017-03-27 17:03:43 +0100
committerChristoffer Dall <cdall@linaro.org>2017-04-09 07:49:15 -0700
commitb6b7a8069d5f44bcc248f5d067cdb22debadfa56 (patch)
tree7c37c64ac262288485512eabf2b3bd59999eb44f /arch/arm64/kvm/sys_regs.c
parentarm64: KVM: Treat sysreg accessors returning false as successful (diff)
downloadlinux-dev-b6b7a8069d5f44bcc248f5d067cdb22debadfa56.tar.xz
linux-dev-b6b7a8069d5f44bcc248f5d067cdb22debadfa56.zip
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 '')
-rw-r--r--arch/arm64/kvm/sys_regs.c27
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, &params, target_specific, nr_specific))
- goto out;
- if (!emulate_cp(vcpu, &params, global, nr_global))
- goto out;
-
- unhandled_cp_access(vcpu, &params);
+ /*
+ * 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, &params, target_specific, nr_specific) ||
+ !emulate_cp(vcpu, &params, 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, &params);
return 1;
}