linux-kernel - [PATCH v2 07/29] LoongArch: KVM: Implement vcpu run interface

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Date:   Mon, 20 Feb 2023 14:57:13 +0800
From:   Tianrui Zhao <zhaotianrui@...ngson.cn>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Huacai Chen <chenhuacai@...nel.org>,
        WANG Xuerui <kernel@...0n.name>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
        Mark Brown <broonie@...nel.org>,
        Alex Deucher <alexander.deucher@....com>,
        Oliver Upton <oliver.upton@...ux.dev>, maobibo@...ngson.cn
Subject: [PATCH v2 07/29] LoongArch: KVM: Implement vcpu run interface

Implement vcpu run interface, handling mmio, iocsr reading fault
and deliver interrupt, lose fpu before vcpu enter guest.

Signed-off-by: Tianrui Zhao <zhaotianrui@...ngson.cn>
---
 arch/loongarch/kvm/vcpu.c | 81 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 4d355bcff..571ac8b9d 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -18,6 +18,26 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
 	return 0;
 }
 
+/* Returns 1 if the guest TLB may be clobbered */
+static int _kvm_check_requests(struct kvm_vcpu *vcpu, int cpu)
+{
+	int ret = 0;
+	int i;
+
+	if (!kvm_request_pending(vcpu))
+		return 0;
+
+	if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
+		/* Drop all vpids for this VCPU */
+		for_each_possible_cpu(i)
+			vcpu->arch.vpid[i] = 0;
+		/* This will clobber guest TLB contents too */
+		ret = 1;
+	}
+
+	return ret;
+}
+
 int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 {
 	int i;
@@ -92,3 +112,64 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 			context->last_vcpu = NULL;
 	}
 }
+
+int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+{
+	int r = -EINTR;
+	int cpu;
+	struct kvm_run *run = vcpu->run;
+
+	vcpu_load(vcpu);
+
+	kvm_sigset_activate(vcpu);
+
+	if (vcpu->mmio_needed) {
+		if (!vcpu->mmio_is_write)
+			_kvm_complete_mmio_read(vcpu, run);
+		vcpu->mmio_needed = 0;
+	}
+
+	if (run->exit_reason == KVM_EXIT_LOONGARCH_IOCSR) {
+		if (!run->iocsr_io.is_write)
+			_kvm_complete_iocsr_read(vcpu, run);
+	}
+
+	/* clear exit_reason */
+	run->exit_reason = KVM_EXIT_UNKNOWN;
+	if (run->immediate_exit)
+		goto out;
+
+	lose_fpu(1);
+
+	local_irq_disable();
+	guest_enter_irqoff();
+	trace_kvm_enter(vcpu);
+
+	/*
+	 * Make sure the read of VCPU requests in vcpu_run() callback is not
+	 * reordered ahead of the write to vcpu->mode, or we could miss a TLB
+	 * flush request while the requester sees the VCPU as outside of guest
+	 * mode and not needing an IPI.
+	 */
+	smp_store_mb(vcpu->mode, IN_GUEST_MODE);
+
+	cpu = smp_processor_id();
+	kvm_acquire_timer(vcpu);
+	/* Check if we have any exceptions/interrupts pending */
+	_kvm_deliver_intr(vcpu);
+
+	_kvm_check_requests(vcpu, cpu);
+	_kvm_check_vmid(vcpu, cpu);
+	vcpu->arch.host_eentry = csr_read64(LOONGARCH_CSR_EENTRY);
+	r = vcpu->arch.vcpu_run(run, vcpu);
+
+	trace_kvm_out(vcpu);
+	guest_exit_irqoff();
+	local_irq_enable();
+
+out:
+	kvm_sigset_deactivate(vcpu);
+
+	vcpu_put(vcpu);
+	return r;
+}
-- 
2.31.1