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linux/arch/riscv/kvm/tlb.S

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RISC-V: KVM: Implement VMID allocator 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 <anup.patel@wdc.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alexander Graf <graf@amazon.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-09-27 17:10:08 +05:30
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2019 Western Digital Corporation or its affiliates.
*
* Authors:
* Anup Patel <anup.patel@wdc.com>
*/
#include <linux/linkage.h>
#include <asm/asm.h>
.text
.altmacro
.option norelax
/*
* Instruction encoding of hfence.gvma is:
* HFENCE.GVMA rs1, rs2
* HFENCE.GVMA zero, rs2
* HFENCE.GVMA rs1
* HFENCE.GVMA
*
* rs1!=zero and rs2!=zero ==> HFENCE.GVMA rs1, rs2
* rs1==zero and rs2!=zero ==> HFENCE.GVMA zero, rs2
* rs1!=zero and rs2==zero ==> HFENCE.GVMA rs1
* rs1==zero and rs2==zero ==> HFENCE.GVMA
*
* Instruction encoding of HFENCE.GVMA is:
* 0110001 rs2(5) rs1(5) 000 00000 1110011
*/
ENTRY(__kvm_riscv_hfence_gvma_vmid_gpa)
/*
RISC-V: KVM: Fix GPA passed to __kvm_riscv_hfence_gvma_xyz() functions The parameter passed to HFENCE.GVMA instruction in rs1 register is guest physical address right shifted by 2 (i.e. divided by 4). Unfortunately, we overlooked the semantics of rs1 registers for HFENCE.GVMA instruction and never right shifted guest physical address by 2. This issue did not manifest for hypervisors till now because: 1) Currently, only __kvm_riscv_hfence_gvma_all() and SBI HFENCE calls are used to invalidate TLB. 2) All H-extension implementations (such as QEMU, Spike, Rocket Core FPGA, etc) that we tried till now were conservatively flushing everything upon any HFENCE.GVMA instruction. This patch fixes GPA passed to __kvm_riscv_hfence_gvma_vmid_gpa() and __kvm_riscv_hfence_gvma_gpa() functions. Fixes: fd7bb4a251df ("RISC-V: KVM: Implement VMID allocator") Reported-by: Ian Huang <ihuang@ventanamicro.com> Signed-off-by: Anup Patel <anup.patel@wdc.com> Message-Id: <20211026170136.2147619-4-anup.patel@wdc.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-26 22:31:36 +05:30
* rs1 = a0 (GPA >> 2)
RISC-V: KVM: Implement VMID allocator 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 <anup.patel@wdc.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alexander Graf <graf@amazon.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-09-27 17:10:08 +05:30
* rs2 = a1 (VMID)
* HFENCE.GVMA a0, a1
* 0110001 01011 01010 000 00000 1110011
*/
.word 0x62b50073
ret
ENDPROC(__kvm_riscv_hfence_gvma_vmid_gpa)
ENTRY(__kvm_riscv_hfence_gvma_vmid)
/*
* rs1 = zero
* rs2 = a0 (VMID)
* HFENCE.GVMA zero, a0
* 0110001 01010 00000 000 00000 1110011
*/
.word 0x62a00073
ret
ENDPROC(__kvm_riscv_hfence_gvma_vmid)
ENTRY(__kvm_riscv_hfence_gvma_gpa)
/*
RISC-V: KVM: Fix GPA passed to __kvm_riscv_hfence_gvma_xyz() functions The parameter passed to HFENCE.GVMA instruction in rs1 register is guest physical address right shifted by 2 (i.e. divided by 4). Unfortunately, we overlooked the semantics of rs1 registers for HFENCE.GVMA instruction and never right shifted guest physical address by 2. This issue did not manifest for hypervisors till now because: 1) Currently, only __kvm_riscv_hfence_gvma_all() and SBI HFENCE calls are used to invalidate TLB. 2) All H-extension implementations (such as QEMU, Spike, Rocket Core FPGA, etc) that we tried till now were conservatively flushing everything upon any HFENCE.GVMA instruction. This patch fixes GPA passed to __kvm_riscv_hfence_gvma_vmid_gpa() and __kvm_riscv_hfence_gvma_gpa() functions. Fixes: fd7bb4a251df ("RISC-V: KVM: Implement VMID allocator") Reported-by: Ian Huang <ihuang@ventanamicro.com> Signed-off-by: Anup Patel <anup.patel@wdc.com> Message-Id: <20211026170136.2147619-4-anup.patel@wdc.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-26 22:31:36 +05:30
* rs1 = a0 (GPA >> 2)
RISC-V: KVM: Implement VMID allocator 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 <anup.patel@wdc.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alexander Graf <graf@amazon.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-09-27 17:10:08 +05:30
* rs2 = zero
* HFENCE.GVMA a0
* 0110001 00000 01010 000 00000 1110011
*/
.word 0x62050073
ret
ENDPROC(__kvm_riscv_hfence_gvma_gpa)
ENTRY(__kvm_riscv_hfence_gvma_all)
/*
* rs1 = zero
* rs2 = zero
* HFENCE.GVMA
* 0110001 00000 00000 000 00000 1110011
*/
.word 0x62000073
ret
ENDPROC(__kvm_riscv_hfence_gvma_all)
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