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Wed, 4 Sep 2019 16:15:22 +0000 From: Anup Patel To: Palmer Dabbelt , Paul Walmsley , Paolo Bonzini , Radim K CC: Daniel Lezcano , Thomas Gleixner , Alexander Graf , Atish Patra , Alistair Francis , Damien Le Moal , Christoph Hellwig , Anup Patel , "kvm@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Anup Patel Subject: [PATCH v7 12/21] RISC-V: KVM: Implement VMID allocator Thread-Topic: [PATCH v7 12/21] RISC-V: KVM: Implement VMID allocator Thread-Index: AQHVYzvzKlzW7GEcQU6sbgtE6GovTw== Date: Wed, 4 Sep 2019 16:15:22 +0000 Message-ID: <20190904161245.111924-14-anup.patel@wdc.com> References: <20190904161245.111924-1-anup.patel@wdc.com> In-Reply-To: <20190904161245.111924-1-anup.patel@wdc.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: MA1PR01CA0084.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a00::24) To MN2PR04MB6061.namprd04.prod.outlook.com (2603:10b6:208:d8::15) authentication-results: spf=none (sender IP is ) smtp.mailfrom=Anup.Patel@wdc.com; x-ms-exchange-messagesentrepresentingtype: 1 x-mailer: git-send-email 2.17.1 x-originating-ip: [49.207.53.222] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 362c54fc-a073-4460-3a50-08d731531636 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(7168020)(4627221)(201703031133081)(201702281549075)(8990200)(5600166)(711020)(4605104)(1401327)(4618075)(2017052603328)(7193020);SRVR:MN2PR04MB5504; x-ms-traffictypediagnostic: MN2PR04MB5504: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: wdcipoutbound: EOP-TRUE x-ms-oob-tlc-oobclassifiers: OLM:8273; x-forefront-prvs: 0150F3F97D x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(4636009)(376002)(136003)(396003)(346002)(366004)(39860400002)(199004)(189003)(66556008)(66446008)(7416002)(7736002)(8676002)(478600001)(25786009)(386003)(66946007)(99286004)(256004)(14444005)(50226002)(14454004)(66476007)(64756008)(6506007)(6512007)(102836004)(6436002)(8936002)(54906003)(6116002)(3846002)(486006)(26005)(55236004)(86362001)(1076003)(53936002)(476003)(316002)(71200400001)(71190400001)(81156014)(76176011)(52116002)(305945005)(5660300002)(6486002)(36756003)(186003)(11346002)(2616005)(66066001)(44832011)(4326008)(2906002)(446003)(81166006)(110136005);DIR:OUT;SFP:1102;SCL:1;SRVR:MN2PR04MB5504;H:MN2PR04MB6061.namprd04.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: SjaTOIFVXEAhTatBwTnYIv8UuiDA+AjxDPrLNUPdCuj96mitAH9a3ga+iV+zm/aimkyOeYT91SmFnlMmSipru1K2TrzeKYb816ggRD79uy6p04ZXhruCfJiVrdUAi6m1dybGWqg5i5pUvkVx6wBDylrD3RkLBW79fI7YZZ+YtEsb7EeCbtoFml2OJWqNz4BwAmaICIXuYxpJtDbTeVjkSVZowxzcJ2HP5b1PZxO3W3b69IISthMVEwdX86uDcmprfy+gmg9yYHeYuAHzr866aahrnWBJiiUQmZjYttYs/PYvN40IxXoJtkVDICamKDKCEkqpjPMZsAr+33+kP81gKW87Oi+xXhTOy1A8Ninr3pNDYI+RgcomL2tCT47Ay5wji3VlfP4x8PdXpSatExoeuw8yrMExAgoHRiOOdwop5is= Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 362c54fc-a073-4460-3a50-08d731531636 X-MS-Exchange-CrossTenant-originalarrivaltime: 04 Sep 2019 16:15:22.2322 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: qJKhQLsgeJS/+Io5GckCTvaC167KN3Q7DOqj2C+wPTlKxUCEb2adsJY844tOqLqEjE07t00oZlYzwKUcPhamIA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR04MB5504 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We implement a simple VMID allocator for Guests/VMs which: 1. Detects number of VMID bits at boot-time 2. Uses atomic number to track VMID version and increments VMID version whenever we run-out of VMIDs 3. Flushes Guest TLBs on all host CPUs whenever we run-out of VMIDs 4. Force updates HW Stage2 VMID for each Guest VCPU whenever VMID changes using VCPU request KVM_REQ_UPDATE_HGATP Signed-off-by: Anup Patel Acked-by: Paolo Bonzini Reviewed-by: Paolo Bonzini Reviewed-by: Alexander Graf --- arch/riscv/include/asm/kvm_host.h | 25 ++++++ arch/riscv/kvm/Makefile | 3 +- arch/riscv/kvm/main.c | 4 + arch/riscv/kvm/tlb.S | 43 +++++++++++ arch/riscv/kvm/vcpu.c | 9 +++ arch/riscv/kvm/vm.c | 6 ++ arch/riscv/kvm/vmid.c | 123 ++++++++++++++++++++++++++++++ 7 files changed, 212 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/kvm/tlb.S create mode 100644 arch/riscv/kvm/vmid.c diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm= _host.h index 2a5209fff68d..8aaf22a900be 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -27,6 +27,7 @@ #define KVM_REQ_SLEEP \ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(1) +#define KVM_REQ_UPDATE_HGATP KVM_ARCH_REQ(2) =20 struct kvm_vm_stat { ulong remote_tlb_flush; @@ -47,7 +48,19 @@ struct kvm_vcpu_stat { struct kvm_arch_memory_slot { }; =20 +struct kvm_vmid { + /* + * Writes to vmid_version and vmid happen with vmid_lock held + * whereas reads happen without any lock held. + */ + unsigned long vmid_version; + unsigned long vmid; +}; + struct kvm_arch { + /* stage2 vmid */ + struct kvm_vmid vmid; + /* stage2 page table */ pgd_t *pgd; phys_addr_t pgd_phys; @@ -170,6 +183,12 @@ static inline void kvm_arch_vcpu_block_finish(struct k= vm_vcpu *vcpu) {} int kvm_riscv_setup_vsip(void); void kvm_riscv_cleanup_vsip(void); =20 +void __kvm_riscv_hfence_gvma_vmid_gpa(unsigned long vmid, + unsigned long gpa); +void __kvm_riscv_hfence_gvma_vmid(unsigned long vmid); +void __kvm_riscv_hfence_gvma_gpa(unsigned long gpa); +void __kvm_riscv_hfence_gvma_all(void); + int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long h= va, bool is_write); void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu); @@ -177,6 +196,12 @@ int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm); void kvm_riscv_stage2_free_pgd(struct kvm *kvm); void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu); =20 +void kvm_riscv_stage2_vmid_detect(void); +unsigned long kvm_riscv_stage2_vmid_bits(void); +int kvm_riscv_stage2_vmid_init(struct kvm *kvm); +bool kvm_riscv_stage2_vmid_ver_changed(struct kvm_vmid *vmid); +void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu); + void __kvm_riscv_unpriv_trap(void); =20 unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu, diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile index 845579273727..c0f57f26c13d 100644 --- a/arch/riscv/kvm/Makefile +++ b/arch/riscv/kvm/Makefile @@ -8,6 +8,7 @@ ccflags-y :=3D -Ivirt/kvm -Iarch/riscv/kvm =20 kvm-objs :=3D $(common-objs-y) =20 -kvm-objs +=3D main.o vm.o mmu.o vcpu.o vcpu_exit.o vcpu_switch.o +kvm-objs +=3D main.o vm.o vmid.o tlb.o mmu.o +kvm-objs +=3D vcpu.o vcpu_exit.o vcpu_switch.o =20 obj-$(CONFIG_KVM) +=3D kvm.o diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c index d088247843c5..55df85184241 100644 --- a/arch/riscv/kvm/main.c +++ b/arch/riscv/kvm/main.c @@ -72,8 +72,12 @@ int kvm_arch_init(void *opaque) if (ret) return ret; =20 + kvm_riscv_stage2_vmid_detect(); + kvm_info("hypervisor extension available\n"); =20 + kvm_info("host has %ld VMID bits\n", kvm_riscv_stage2_vmid_bits()); + return 0; } =20 diff --git a/arch/riscv/kvm/tlb.S b/arch/riscv/kvm/tlb.S new file mode 100644 index 000000000000..453fca8d7940 --- /dev/null +++ b/arch/riscv/kvm/tlb.S @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel + */ + +#include +#include + + .text + .altmacro + .option norelax + + /* + * Instruction encoding of hfence.gvma is: + * 0110001 rs2(5) rs1(5) 000 00000 1110011 + */ + +ENTRY(__kvm_riscv_hfence_gvma_vmid_gpa) + /* hfence.gvma a1, a0 */ + .word 0x62a60073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_vmid_gpa) + +ENTRY(__kvm_riscv_hfence_gvma_vmid) + /* hfence.gvma zero, a0 */ + .word 0x62a00073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_vmid) + +ENTRY(__kvm_riscv_hfence_gvma_gpa) + /* hfence.gvma a0 */ + .word 0x62050073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_gpa) + +ENTRY(__kvm_riscv_hfence_gvma_all) + /* hfence.gvma */ + .word 0x62000073 + ret +ENDPROC(__kvm_riscv_hfence_gvma_all) diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 7f1f07badaad..66158c0b90e6 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -637,6 +637,12 @@ static void kvm_riscv_check_vcpu_requests(struct kvm_v= cpu *vcpu) =20 if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu)) kvm_riscv_reset_vcpu(vcpu); + + if (kvm_check_request(KVM_REQ_UPDATE_HGATP, vcpu)) + kvm_riscv_stage2_update_hgatp(vcpu); + + if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) + __kvm_riscv_hfence_gvma_all(); } } =20 @@ -699,6 +705,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, stru= ct kvm_run *run) /* Check conditions before entering the guest */ cond_resched(); =20 + kvm_riscv_stage2_vmid_update(vcpu); + kvm_riscv_check_vcpu_requests(vcpu); =20 preempt_disable(); @@ -735,6 +743,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, stru= ct kvm_run *run) kvm_riscv_update_vsip(vcpu); =20 if (ret <=3D 0 || + kvm_riscv_stage2_vmid_ver_changed(&vcpu->kvm->arch.vmid) || kvm_request_pending(vcpu)) { vcpu->mode =3D OUTSIDE_GUEST_MODE; local_irq_enable(); diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index ac0211820521..c5aab5478c38 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -26,6 +26,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type= ) if (r) return r; =20 + r =3D kvm_riscv_stage2_vmid_init(kvm); + if (r) { + kvm_riscv_stage2_free_pgd(kvm); + return r; + } + return 0; } =20 diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c new file mode 100644 index 000000000000..69f770fa4f46 --- /dev/null +++ b/arch/riscv/kvm/vmid.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel + */ + +#include +#include +#include +#include +#include +#include +#include + +static unsigned long vmid_version =3D 1; +static unsigned long vmid_next; +static unsigned long vmid_bits; +static DEFINE_SPINLOCK(vmid_lock); + +void kvm_riscv_stage2_vmid_detect(void) +{ + unsigned long old; + + /* Figure-out number of VMID bits in HW */ + old =3D csr_read(CSR_HGATP); + csr_write(CSR_HGATP, old | HGATP_VMID_MASK); + vmid_bits =3D csr_read(CSR_HGATP); + vmid_bits =3D (vmid_bits & HGATP_VMID_MASK) >> HGATP_VMID_SHIFT; + vmid_bits =3D fls_long(vmid_bits); + csr_write(CSR_HGATP, old); + + /* We polluted local TLB so flush all guest TLB */ + __kvm_riscv_hfence_gvma_all(); + + /* We don't use VMID bits if they are not sufficient */ + if ((1UL << vmid_bits) < num_possible_cpus()) + vmid_bits =3D 0; +} + +unsigned long kvm_riscv_stage2_vmid_bits(void) +{ + return vmid_bits; +} + +int kvm_riscv_stage2_vmid_init(struct kvm *kvm) +{ + /* Mark the initial VMID and VMID version invalid */ + kvm->arch.vmid.vmid_version =3D 0; + kvm->arch.vmid.vmid =3D 0; + + return 0; +} + +static void local_guest_tlb_flush_all(void *info) +{ + __kvm_riscv_hfence_gvma_all(); +} + +bool kvm_riscv_stage2_vmid_ver_changed(struct kvm_vmid *vmid) +{ + if (!vmid_bits) + return false; + + return unlikely(READ_ONCE(vmid->vmid_version) !=3D + READ_ONCE(vmid_version)); +} + +void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu) +{ + int i; + struct kvm_vcpu *v; + struct kvm_vmid *vmid =3D &vcpu->kvm->arch.vmid; + + if (!kvm_riscv_stage2_vmid_ver_changed(vmid)) + return; + + spin_lock(&vmid_lock); + + /* + * We need to re-check the vmid_version here to ensure that if + * another vcpu already allocated a valid vmid for this vm. + */ + if (!kvm_riscv_stage2_vmid_ver_changed(vmid)) { + spin_unlock(&vmid_lock); + return; + } + + /* First user of a new VMID version? */ + if (unlikely(vmid_next =3D=3D 0)) { + WRITE_ONCE(vmid_version, READ_ONCE(vmid_version) + 1); + vmid_next =3D 1; + + /* + * We ran out of VMIDs so we increment vmid_version and + * start assigning VMIDs from 1. + * + * This also means existing VMIDs assignement to all Guest + * instances is invalid and we have force VMID re-assignement + * for all Guest instances. The Guest instances that were not + * running will automatically pick-up new VMIDs because will + * call kvm_riscv_stage2_vmid_update() whenever they enter + * in-kernel run loop. For Guest instances that are already + * running, we force VM exits on all host CPUs using IPI and + * flush all Guest TLBs. + */ + smp_call_function_many(cpu_online_mask, + local_guest_tlb_flush_all, NULL, true); + } + + vmid->vmid =3D vmid_next; + vmid_next++; + vmid_next &=3D (1 << vmid_bits) - 1; + + WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version)); + + spin_unlock(&vmid_lock); + + /* Request stage2 page table update for all VCPUs */ + kvm_for_each_vcpu(i, v, vcpu->kvm) + kvm_make_request(KVM_REQ_UPDATE_HGATP, v); +} --=20 2.17.1