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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
RISC-V: KVM: Implement SBI STA extension
Add a select SCHED_INFO to the KVM config in order to get run_delay
info. Then implement SBI STA's set-steal-time-shmem function and
kvm_riscv_vcpu_record_steal_time() to provide the steal-time info
to guests.
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
authored by
Andrew Jones
and committed by
Anup Patel
e9f12b5f
f61ce890
+95
-2
+1
arch/riscv/kvm/Kconfig
+1
arch/riscv/kvm/Kconfig
+94
-2
arch/riscv/kvm/vcpu_sbi_sta.c
+94
-2
arch/riscv/kvm/vcpu_sbi_sta.c
···
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#include <linux/kconfig.h>
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#include <linux/kernel.h>
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#include <linux/kvm_host.h>
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#include <linux/mm.h>
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#include <linux/sizes.h>
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#include <asm/bug.h>
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#include <asm/current.h>
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#include <asm/kvm_vcpu_sbi.h>
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#include <asm/page.h>
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#include <asm/sbi.h>
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#include <asm/uaccess.h>
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void kvm_riscv_vcpu_sbi_sta_reset(struct kvm_vcpu *vcpu)
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{
···
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void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu)
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{
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gpa_t shmem = vcpu->arch.sta.shmem;
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u64 last_steal = vcpu->arch.sta.last_steal;
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u32 *sequence_ptr, sequence;
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u64 *steal_ptr, steal;
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unsigned long hva;
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gfn_t gfn;
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if (shmem == INVALID_GPA)
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return;
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/*
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* shmem is 64-byte aligned (see the enforcement in
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* kvm_sbi_sta_steal_time_set_shmem()) and the size of sbi_sta_struct
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* is 64 bytes, so we know all its offsets are in the same page.
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*/
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gfn = shmem >> PAGE_SHIFT;
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hva = kvm_vcpu_gfn_to_hva(vcpu, gfn);
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if (WARN_ON(kvm_is_error_hva(hva))) {
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vcpu->arch.sta.shmem = INVALID_GPA;
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return;
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}
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sequence_ptr = (u32 *)(hva + offset_in_page(shmem) +
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offsetof(struct sbi_sta_struct, sequence));
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steal_ptr = (u64 *)(hva + offset_in_page(shmem) +
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offsetof(struct sbi_sta_struct, steal));
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if (WARN_ON(get_user(sequence, sequence_ptr)))
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return;
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sequence = le32_to_cpu(sequence);
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sequence += 1;
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if (WARN_ON(put_user(cpu_to_le32(sequence), sequence_ptr)))
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return;
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if (!WARN_ON(get_user(steal, steal_ptr))) {
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steal = le64_to_cpu(steal);
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vcpu->arch.sta.last_steal = READ_ONCE(current->sched_info.run_delay);
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steal += vcpu->arch.sta.last_steal - last_steal;
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WARN_ON(put_user(cpu_to_le64(steal), steal_ptr));
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}
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sequence += 1;
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WARN_ON(put_user(cpu_to_le32(sequence), sequence_ptr));
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kvm_vcpu_mark_page_dirty(vcpu, gfn);
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}
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static int kvm_sbi_sta_steal_time_set_shmem(struct kvm_vcpu *vcpu)
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{
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return SBI_ERR_FAILURE;
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struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
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unsigned long shmem_phys_lo = cp->a0;
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unsigned long shmem_phys_hi = cp->a1;
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u32 flags = cp->a2;
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struct sbi_sta_struct zero_sta = {0};
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unsigned long hva;
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bool writable;
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gpa_t shmem;
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int ret;
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if (flags != 0)
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return SBI_ERR_INVALID_PARAM;
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if (shmem_phys_lo == SBI_STA_SHMEM_DISABLE &&
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shmem_phys_hi == SBI_STA_SHMEM_DISABLE) {
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vcpu->arch.sta.shmem = INVALID_GPA;
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return 0;
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}
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if (shmem_phys_lo & (SZ_64 - 1))
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return SBI_ERR_INVALID_PARAM;
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shmem = shmem_phys_lo;
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if (shmem_phys_hi != 0) {
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if (IS_ENABLED(CONFIG_32BIT))
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shmem |= ((gpa_t)shmem_phys_hi << 32);
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else
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return SBI_ERR_INVALID_ADDRESS;
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}
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hva = kvm_vcpu_gfn_to_hva_prot(vcpu, shmem >> PAGE_SHIFT, &writable);
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if (kvm_is_error_hva(hva) || !writable)
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return SBI_ERR_INVALID_ADDRESS;
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ret = kvm_vcpu_write_guest(vcpu, shmem, &zero_sta, sizeof(zero_sta));
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if (ret)
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return SBI_ERR_FAILURE;
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vcpu->arch.sta.shmem = shmem;
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vcpu->arch.sta.last_steal = current->sched_info.run_delay;
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return 0;
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}
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static int kvm_sbi_ext_sta_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
···
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static unsigned long kvm_sbi_ext_sta_probe(struct kvm_vcpu *vcpu)
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{
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return 0;
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return !!sched_info_on();
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}
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const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta = {