linux-kernel - [PATCH v2 08/15] arm64: KVM/debug: drop pmscr_el1 and use sys_regs[PMSCR_EL1] in kvm_cpu

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Message-Id: <20190523103502.25925-9-sudeep.holla@arm.com>
Date:   Thu, 23 May 2019 11:34:55 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     kvmarm@...ts.cs.columbia.edu, linux-arm-kernel@...ts.infradead.org
Cc:     Sudeep Holla <sudeep.holla@....com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Christoffer Dall <christoffer.dall@....com>,
        Marc Zyngier <marc.zyngier@....com>,
        James Morse <james.morse@....com>,
        Suzuki K Pouloze <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Julien Thierry <julien.thierry@....com>
Subject: [PATCH v2 08/15] arm64: KVM/debug: drop pmscr_el1 and use sys_regs[PMSCR_EL1] in kvm_cpu_context

kvm_cpu_context now has support to stash the complete SPE buffer control
context. We no longer need the pmscr_el1 kvm_vcpu_arch and it can be
dropped.

Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 arch/arm64/include/asm/kvm_host.h |  2 --
 arch/arm64/kvm/hyp/debug-sr.c     | 26 +++++++++++++++-----------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 559aa6931291..6921fdfd477b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -310,8 +310,6 @@ struct kvm_vcpu_arch {
 	struct {
 		/* {Break,watch}point registers */
 		struct kvm_guest_debug_arch regs;
-		/* Statistical profiling extension */
-		u64 pmscr_el1;
 	} host_debug_state;
 
 	/* VGIC state */
diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c
index 618884df1dc4..a2714a5eb3e9 100644
--- a/arch/arm64/kvm/hyp/debug-sr.c
+++ b/arch/arm64/kvm/hyp/debug-sr.c
@@ -66,19 +66,19 @@
 	default:	write_debug(ptr[0], reg, 0);			\
 	}
 
-static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1)
+static void __hyp_text __debug_save_spe_nvhe(struct kvm_cpu_context *ctxt)
 {
 	u64 reg;
 
 	/* Clear pmscr in case of early return */
-	*pmscr_el1 = 0;
+	ctxt->sys_regs[PMSCR_EL1] = 0;
 
 	/* SPE present on this CPU? */
 	if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
 						  ID_AA64DFR0_PMSVER_SHIFT))
 		return;
 
-	/* Yes; is it owned by EL3? */
+	/* Yes; is it owned by higher EL? */
 	reg = read_sysreg_s(SYS_PMBIDR_EL1);
 	if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT))
 		return;
@@ -89,7 +89,7 @@ static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1)
 		return;
 
 	/* Yes; save the control register and disable data generation */
-	*pmscr_el1 = read_sysreg_el1_s(SYS_PMSCR);
+	ctxt->sys_regs[PMSCR_EL1] = read_sysreg_el1_s(SYS_PMSCR);
 	write_sysreg_el1_s(0, SYS_PMSCR);
 	isb();
 
@@ -98,16 +98,16 @@ static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1)
 	dsb(nsh);
 }
 
-static void __hyp_text __debug_restore_spe_nvhe(u64 pmscr_el1)
+static void __hyp_text __debug_restore_spe_nvhe(struct kvm_cpu_context *ctxt)
 {
-	if (!pmscr_el1)
+	if (!ctxt->sys_regs[PMSCR_EL1])
 		return;
 
 	/* The host page table is installed, but not yet synchronised */
 	isb();
 
 	/* Re-enable data generation */
-	write_sysreg_el1_s(pmscr_el1, SYS_PMSCR);
+	write_sysreg_el1_s(ctxt->sys_regs[PMSCR_EL1], SYS_PMSCR);
 }
 
 static void __hyp_text __debug_save_state(struct kvm_vcpu *vcpu,
@@ -175,14 +175,15 @@ void __hyp_text __debug_restore_host_context(struct kvm_vcpu *vcpu)
 	struct kvm_guest_debug_arch *host_dbg;
 	struct kvm_guest_debug_arch *guest_dbg;
 
+	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
+	guest_ctxt = &vcpu->arch.ctxt;
+
 	if (!has_vhe())
-		__debug_restore_spe_nvhe(vcpu->arch.host_debug_state.pmscr_el1);
+		__debug_restore_spe_nvhe(host_ctxt);
 
 	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
 
-	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
-	guest_ctxt = &vcpu->arch.ctxt;
 	host_dbg = &vcpu->arch.host_debug_state.regs;
 	guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr);
 
@@ -198,8 +199,11 @@ void __hyp_text __debug_save_host_context(struct kvm_vcpu *vcpu)
 	 * Non-VHE: Disable and flush SPE data generation
 	 * VHE: The vcpu can run, but it can't hide.
 	 */
+	struct kvm_cpu_context *host_ctxt;
+
+	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 	if (!has_vhe())
-		__debug_save_spe_nvhe(&vcpu->arch.host_debug_state.pmscr_el1);
+		__debug_save_spe_nvhe(host_ctxt);
 }
 
 void __hyp_text __debug_save_guest_context(struct kvm_vcpu *vcpu)
-- 
2.17.1