Hi James,
  thanks for the review.

On 2018/1/24 3:07, James Morse wrote:

Hi Dongjiu Geng,

On 06/01/18 16:02, Dongjiu Geng wrote:

quoted

RAS Extension add a VSESR_EL2 register which can provide
the syndrome value reported to software on taking a virtual
SError interrupt exception. This patch supports to specify
this Syndrome.

In the RAS Extensions we can not set all-zero syndrome value
for SError, which means 'RAS error: Uncategorized' instead of
'no valid ISS'. So set it to IMPLEMENTATION DEFINED syndrome
by default.

We also need to support userspace to specify a valid syndrome
value, Because in some case, the recovery is driven by userspace.
This patch can support that userspace specify it.

In the guest/host world switch, restore this value to VSESR_EL2
only when HCR_EL2.VSE is set. This value no need to be saved
because it is stale vale when guest exit.

A version of this patch has been queued by Catalin.

yeah, I have seen that.

Now that the cpufeature bits are queued, I think this can be split up into two
separate series for v4.16-rc1, one to tackle NOTIFY_SEI and the associated
plumbing. The second for the KVM 'make SError pending' API.

quoted

Signed-off-by: Dongjiu Geng <redacted>
[Set an impdef ESR for Virtual-SError]
Signed-off-by: James Morse <james.morse@arm.com>

I didn't sign-off this patch. If you pick some bits from another version and
want to credit someone else you can 'CC:' them or just mention it in the
commit-message.

I pick your modification of setting an impdef ESR for Virtual-SError, so add your name,
I change it to 'CC'

quoted

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 47b967d..3b035cc 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h

@@ -86,6 +86,9 @@
 #define REG_PSTATE_PAN_IMM		sys_reg(0, 0, 4, 0, 4)
 #define REG_PSTATE_UAO_IMM		sys_reg(0, 0, 4, 0, 3)
 
+/* virtual SError exception syndrome register */
+#define REG_VSESR_EL2                  sys_reg(3, 4, 5, 2, 3)

Irrelevant-Nit: sys-regs usually have a 'SYS_' prefix, and are in instruction
encoding order lower down the file.

will follow that.

(These PSTATE PAN things are a bit odd as they were used to generate and
instruction before the fancy {read,write}_sysreg() helpers were added).>

quoted

 #define SET_PSTATE_PAN(x) __emit_inst(0xd5000000 | REG_PSTATE_PAN_IMM |	\
 				      (!!x)<<8 | 0x1f)
 #define SET_PSTATE_UAO(x) __emit_inst(0xd5000000 | REG_PSTATE_UAO_IMM |	\

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 738ae90..ffad42b 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c

@@ -279,7 +279,16 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 
 int kvm_arm_set_sei_esr(struct kvm_vcpu *vcpu, u32 *syndrome)

Bits of this are spread between patches 5 and 6. If you put them in the other
order this wouldn't happen.

Ok, I will adjust that.

(but after a rebase most of this patch should disappear)

quoted

 {
-	return -EINVAL;
+	u64 reg = *syndrome;
+
+	/* inject virtual system Error or asynchronous abort */
+	kvm_inject_vabt(vcpu);

So this writes an impdef ESR, because its the existing code-path in KVM.

quoted

+	if (reg)
+		/* set vsesr_el2[24:0] with value that user space specified */
+		kvm_vcpu_set_vsesr(vcpu, reg & ESR_ELx_ISS_MASK);

And then you overwrite it. Which is a bit odd as there is a helper to do both in
one go:

thanks, I will directly call pend_guest_serror() in this function.

quoted

+
+	return 0;
 }

quoted

 int __attribute_const__ kvm_target_cpu(void)

quoted

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 3556715..fb94b5e 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c

@@ -246,14 +246,25 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 		inject_undef64(vcpu);
 }
 
+static void pend_guest_serror(struct kvm_vcpu *vcpu, u64 esr)
+{
+	kvm_vcpu_set_vsesr(vcpu, esr);
+	vcpu_set_hcr(vcpu, vcpu_get_hcr(vcpu) | HCR_VSE);
+}

How come you don't use this in kvm_arm_set_sei_esr()?

thanks, I will call pend_guest_serror() in the kvm_arm_set_sei_esr().

Thanks,

James

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