On Fri, May 24, 2019 at 12:36:24PM +0100, Julien Thierry wrote:

Hi Sudeep,

On 23/05/2019 11:34, Sudeep Holla wrote:

quoted

SPE Profiling Buffer owning EL is configurable and when MDCR_EL2.E2PB
is configured to provide buffer ownership to EL1, the control registers
are trapped.

Add access handlers for the Statistical Profiling Extension(SPE)
Profiling Buffer controls registers. This is need to support profiling
using SPE in the guests.

Signed-off-by: Sudeep Holla <redacted>
---
 arch/arm64/include/asm/kvm_host.h | 13 ++++++++++++
 arch/arm64/kvm/sys_regs.c         | 35 +++++++++++++++++++++++++++++++
 include/kvm/arm_spe.h             | 15 +++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 611a4884fb6c..559aa6931291 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h

@@ -147,6 +147,19 @@ enum vcpu_sysreg {
 	MDCCINT_EL1,	/* Monitor Debug Comms Channel Interrupt Enable Reg */
 	DISR_EL1,	/* Deferred Interrupt Status Register */
 
+	/* Statistical Profiling Extension Registers */
+
+	PMSCR_EL1,
+	PMSICR_EL1,
+	PMSIRR_EL1,
+	PMSFCR_EL1,
+	PMSEVFR_EL1,
+	PMSLATFR_EL1,
+	PMSIDR_EL1,
+	PMBLIMITR_EL1,
+	PMBPTR_EL1,
+	PMBSR_EL1,
+
 	/* Performance Monitors Registers */
 	PMCR_EL0,	/* Control Register */
 	PMSELR_EL0,	/* Event Counter Selection Register */

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 857b226bcdde..dbf5056828d3 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c

@@ -646,6 +646,30 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	__vcpu_sys_reg(vcpu, PMCR_EL0) = val;
 }
 
+static bool access_pmsb_val(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			    const struct sys_reg_desc *r)
+{
+	if (p->is_write)
+		vcpu_write_sys_reg(vcpu, p->regval, r->reg);
+	else
+		p->regval = vcpu_read_sys_reg(vcpu, r->reg);
+
+	return true;
+}
+
+static void reset_pmsb_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	if (!kvm_arm_support_spe_v1()) {
+		__vcpu_sys_reg(vcpu, r->reg) = 0;
+		return;
+	}
+
+	if (r->reg == PMSIDR_EL1)

If only PMSIDR_EL1 has a non-zero reset value, it feels a bit weird to
share the reset function for all these registers.

Ah, right. Initially I did have couple of other registers which were not
needed. So I removed them without observing that I could have just used
reset_val(0) for all except PMSIDR_EL1.

I would suggest only having a reset_pmsidr() function, and just use
reset_val() with sys_reg_desc->val set to 0 for all the others.

Thanks for pointing this out.

--
Regards,
Sudeep

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