Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Usama Arif <usama.arif@bytedance.com>
To:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
        linux-doc@vger.kernel.org,
        virtualization@lists.linux-foundation.org, linux@armlinux.org.uk,
        yezengruan@huawei.com, catalin.marinas@arm.com, will@kernel.org,
        maz@kernel.org, steven.price@arm.com, mark.rutland@arm.com,
        bagasdotme@gmail.com
Cc:     fam.zheng@bytedance.com, liangma@liangbit.com,
        punit.agrawal@bytedance.com, Usama Arif <usama.arif@bytedance.com>
Subject: [v2 3/6] KVM: arm64: Support pvlock preempted via shared structure
Date:   Fri,  4 Nov 2022 06:21:02 +0000
Message-Id: <20221104062105.4119003-4-usama.arif@bytedance.com>
In-Reply-To: <20221104062105.4119003-1-usama.arif@bytedance.com>
References: <20221104062105.4119003-1-usama.arif@bytedance.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Implement the service call for configuring a shared structure between a
VCPU and the hypervisor in which the hypervisor can tell whether the
VCPU is running or not.

The preempted field is zero if the VCPU is not preempted.
Any other value means the VCPU has been preempted.

Signed-off-by: Zengruan Ye <yezengruan@huawei.com>
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
---
 Documentation/virt/kvm/arm/hypercalls.rst |  3 ++
 arch/arm64/include/asm/kvm_host.h         | 18 ++++++++++
 arch/arm64/include/uapi/asm/kvm.h         |  1 +
 arch/arm64/kvm/Makefile                   |  2 +-
 arch/arm64/kvm/arm.c                      |  8 +++++
 arch/arm64/kvm/hypercalls.c               |  8 +++++
 arch/arm64/kvm/pvlock.c                   | 43 +++++++++++++++++++++++
 tools/arch/arm64/include/uapi/asm/kvm.h   |  1 +
 8 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/kvm/pvlock.c

diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst
index 3e23084644ba..872a16226ace 100644
--- a/Documentation/virt/kvm/arm/hypercalls.rst
+++ b/Documentation/virt/kvm/arm/hypercalls.rst
@@ -127,6 +127,9 @@ The pseudo-firmware bitmap register are as follows:
     Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP:
       The bit represents the Precision Time Protocol KVM service.
 
+    Bit-2: KVM_REG_ARM_VENDOR_HYP_BIT_PV_LOCK:
+      The bit represents the Paravirtualized lock service.
+
 Errors:
 
     =======  =============================================================
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 45e2136322ba..18303b30b7e9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -417,6 +417,11 @@ struct kvm_vcpu_arch {
 		u64 last_steal;
 		gpa_t base;
 	} steal;
+
+	/* Guest PV lock state */
+	struct {
+		gpa_t base;
+	} pv;
 };
 
 /*
@@ -840,6 +845,19 @@ static inline bool kvm_arm_is_pvtime_enabled(struct kvm_vcpu_arch *vcpu_arch)
 	return (vcpu_arch->steal.base != GPA_INVALID);
 }
 
+static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch *vcpu_arch)
+{
+	vcpu_arch->pv.base = GPA_INVALID;
+}
+
+static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch *vcpu_arch)
+{
+	return (vcpu_arch->pv.base != GPA_INVALID);
+}
+
+gpa_t kvm_init_pvlock(struct kvm_vcpu *vcpu);
+void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64 preempted);
+
 void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);
 
 struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 316917b98707..bd05ece5c590 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -365,6 +365,7 @@ enum {
 enum {
 	KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT	= 0,
 	KVM_REG_ARM_VENDOR_HYP_BIT_PTP		= 1,
+	KVM_REG_ARM_VENDOR_HYP_BIT_PV_LOCK	= 2,
 #ifdef __KERNEL__
 	KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT,
 #endif
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 5e33c2d4645a..e1f711885916 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -10,7 +10,7 @@ include $(srctree)/virt/kvm/Makefile.kvm
 obj-$(CONFIG_KVM) += kvm.o
 obj-$(CONFIG_KVM) += hyp/
 
-kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
+kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o pvlock.o \
 	 inject_fault.o va_layout.o handle_exit.o \
 	 guest.o debug.o reset.o sys_regs.o stacktrace.o \
 	 vgic-sys-reg-v3.o fpsimd.o pkvm.o \
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 94d33e296e10..73da4ac859fd 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -345,6 +345,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 	kvm_arm_pvtime_vcpu_init(&vcpu->arch);
 
+	kvm_arm_pvlock_preempted_init(&vcpu->arch);
+
 	vcpu->arch.hw_mmu = &vcpu->kvm->arch.mmu;
 
 	err = kvm_vgic_vcpu_init(vcpu);
@@ -420,6 +422,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	if (vcpu_has_ptrauth(vcpu))
 		vcpu_ptrauth_disable(vcpu);
+
+	if (kvm_arm_is_pvlock_preempted_ready(&vcpu->arch))
+		kvm_update_pvlock_preempted(vcpu, 0);
+
 	kvm_arch_vcpu_load_debug_state_flags(vcpu);
 
 	if (!cpumask_test_cpu(smp_processor_id(), vcpu->kvm->arch.supported_cpus))
@@ -433,6 +439,8 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 	if (has_vhe())
 		kvm_vcpu_put_sysregs_vhe(vcpu);
 	kvm_timer_vcpu_put(vcpu);
+	if (kvm_arm_is_pvlock_preempted_ready(&vcpu->arch))
+		kvm_update_pvlock_preempted(vcpu, 1);
 	kvm_vgic_put(vcpu);
 	kvm_vcpu_pmu_restore_host(vcpu);
 	kvm_arm_vmid_clear_active();
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index c9f401fa01a9..ec85b4b2a272 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -116,6 +116,9 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
 	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
 		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
 				&smccc_feat->vendor_hyp_bmap);
+	case ARM_SMCCC_VENDOR_HYP_KVM_PV_LOCK_FUNC_ID:
+		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PV_LOCK,
+				&smccc_feat->vendor_hyp_bmap);
 	default:
 		return kvm_hvc_call_default_allowed(func_id);
 	}
@@ -201,6 +204,11 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 		if (gpa != GPA_INVALID)
 			val[0] = gpa;
 		break;
+	case ARM_SMCCC_VENDOR_HYP_KVM_PV_LOCK_FUNC_ID:
+		gpa = kvm_init_pvlock(vcpu);
+		if (gpa != GPA_INVALID)
+			val[0] = gpa;
+		break;
 	case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
 		val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0;
 		val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1;
diff --git a/arch/arm64/kvm/pvlock.c b/arch/arm64/kvm/pvlock.c
new file mode 100644
index 000000000000..3eb35ab31481
--- /dev/null
+++ b/arch/arm64/kvm/pvlock.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ * Author: Zengruan Ye <yezengruan@huawei.com>
+ *         Usama Arif <usama.arif@bytedance.com>
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/kvm_host.h>
+
+#include <asm/pvlock-abi.h>
+
+#include <kvm/arm_hypercalls.h>
+
+gpa_t kvm_init_pvlock(struct kvm_vcpu *vcpu)
+{
+	struct pvlock_vcpu_state init_values = {};
+	struct kvm *kvm = vcpu->kvm;
+	u64 base = vcpu->arch.pv.base;
+	int idx;
+
+	if (base == GPA_INVALID)
+		return base;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	kvm_write_guest(kvm, base, &init_values, sizeof(init_values));
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return base;
+}
+
+void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64 preempted)
+{
+	int idx;
+	u64 offset;
+	struct kvm *kvm = vcpu->kvm;
+	u64 base = vcpu->arch.pv.base;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	offset = offsetof(struct pvlock_vcpu_state, preempted);
+	kvm_put_guest(kvm, base + offset, cpu_to_le64(preempted));
+	srcu_read_unlock(&kvm->srcu, idx);
+}
diff --git a/tools/arch/arm64/include/uapi/asm/kvm.h b/tools/arch/arm64/include/uapi/asm/kvm.h
index 316917b98707..bd05ece5c590 100644
--- a/tools/arch/arm64/include/uapi/asm/kvm.h
+++ b/tools/arch/arm64/include/uapi/asm/kvm.h
@@ -365,6 +365,7 @@ enum {
 enum {
 	KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT	= 0,
 	KVM_REG_ARM_VENDOR_HYP_BIT_PTP		= 1,
+	KVM_REG_ARM_VENDOR_HYP_BIT_PV_LOCK	= 2,
 #ifdef __KERNEL__
 	KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT,
 #endif
-- 
2.25.1