| Message ID | 20210913135745.13944-3-jgross@suse.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kvm: fix KVM_MAX_VCPU_ID handling | expand |
On Mon, Sep 13, 2021, Juergen Gross wrote: > KVM_MAX_VCPU_ID is not specifying the highest allowed vcpu-id, but the > number of allowed vcpu-ids. This has already led to confusion, so > rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDS to make its semantics more > clear My hesitation with this rename is that the max _number_ of IDs is not the same thing as the max allowed ID. E.g. on x86, given a capability that enumerates the max number of IDs, I would expect to be able to create vCPUs with arbitrary 32-bit x2APIC IDs so long as the total number of IDs is below the max.
On Mon, Sep 13, 2021 at 12:24 PM Sean Christopherson <seanjc@google.com> wrote: > > On Mon, Sep 13, 2021, Juergen Gross wrote: > > KVM_MAX_VCPU_ID is not specifying the highest allowed vcpu-id, but the > > number of allowed vcpu-ids. This has already led to confusion, so > > rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDS to make its semantics more > > clear > > My hesitation with this rename is that the max _number_ of IDs is not the same > thing as the max allowed ID. E.g. on x86, given a capability that enumerates the > max number of IDs, I would expect to be able to create vCPUs with arbitrary 32-bit > x2APIC IDs so long as the total number of IDs is below the max. > What name would you suggest instead? KVM_VCPU_ID_LIMIT, maybe? I'm assuming we are not going to redefine KVM_MAX_VCPU_ID to be an inclusive limit. -- Eduardo
On Mon, Sep 13, 2021, Eduardo Habkost wrote: > On Mon, Sep 13, 2021 at 12:24 PM Sean Christopherson <seanjc@google.com> wrote: > > > > On Mon, Sep 13, 2021, Juergen Gross wrote: > > > KVM_MAX_VCPU_ID is not specifying the highest allowed vcpu-id, but the > > > number of allowed vcpu-ids. This has already led to confusion, so > > > rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDS to make its semantics more > > > clear > > > > My hesitation with this rename is that the max _number_ of IDs is not the same > > thing as the max allowed ID. E.g. on x86, given a capability that enumerates the > > max number of IDs, I would expect to be able to create vCPUs with arbitrary 32-bit > > x2APIC IDs so long as the total number of IDs is below the max. > > > > What name would you suggest instead? KVM_VCPU_ID_LIMIT, maybe? > > I'm assuming we are not going to redefine KVM_MAX_VCPU_ID to be an > inclusive limit. Heh, I haven't been able to come up with one, which is why I suggested the route of making it an inclusive value internally within KVM.
diff --git a/Documentation/virt/kvm/devices/xics.rst b/Documentation/virt/kvm/devices/xics.rst index 2d6927e0b776..bf32c77174ab 100644 --- a/Documentation/virt/kvm/devices/xics.rst +++ b/Documentation/virt/kvm/devices/xics.rst @@ -22,7 +22,7 @@ Groups: Errors: ======= ========================================== - -EINVAL Value greater than KVM_MAX_VCPU_ID. + -EINVAL Value greater than KVM_MAX_VCPU_IDS. -EFAULT Invalid user pointer for attr->addr. -EBUSY A vcpu is already connected to the device. ======= ========================================== diff --git a/Documentation/virt/kvm/devices/xive.rst b/Documentation/virt/kvm/devices/xive.rst index 8bdf3dc38f01..8b5e7b40bdf8 100644 --- a/Documentation/virt/kvm/devices/xive.rst +++ b/Documentation/virt/kvm/devices/xive.rst @@ -91,7 +91,7 @@ the legacy interrupt mode, referred as XICS (POWER7/8). Errors: ======= ========================================== - -EINVAL Value greater than KVM_MAX_VCPU_ID. + -EINVAL Value greater than KVM_MAX_VCPU_IDS. -EFAULT Invalid user pointer for attr->addr. -EBUSY A vCPU is already connected to the device. ======= ========================================== diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 75c6f264c626..562aa878b266 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -1073,7 +1073,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_MAX_VCPUS; break; case KVM_CAP_MAX_VCPU_ID: - r = KVM_MAX_VCPU_ID; + r = KVM_MAX_VCPU_IDS; break; case KVM_CAP_MIPS_FPU: /* We don't handle systems with inconsistent cpu_has_fpu */ diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index caaa0f592d8e..3d31f2c59e43 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -434,7 +434,7 @@ extern int kvmppc_h_logical_ci_store(struct kvm_vcpu *vcpu); #define SPLIT_HACK_OFFS 0xfb000000 /* - * This packs a VCPU ID from the [0..KVM_MAX_VCPU_ID) space down to the + * This packs a VCPU ID from the [0..KVM_MAX_VCPU_IDS) space down to the * [0..KVM_MAX_VCPUS) space, using knowledge of the guest's core stride * (but not its actual threading mode, which is not available) to avoid * collisions. diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 080a7feb7731..59cb38b04ede 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -33,11 +33,11 @@ #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE #include <asm/kvm_book3s_asm.h> /* for MAX_SMT_THREADS */ -#define KVM_MAX_VCPU_ID (MAX_SMT_THREADS * KVM_MAX_VCORES) +#define KVM_MAX_VCPU_IDS (MAX_SMT_THREADS * KVM_MAX_VCORES) #define KVM_MAX_NESTED_GUESTS KVMPPC_NR_LPIDS #else -#define KVM_MAX_VCPU_ID KVM_MAX_VCPUS +#define KVM_MAX_VCPU_IDS KVM_MAX_VCPUS #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */ #define __KVM_HAVE_ARCH_INTC_INITIALIZED diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c index a18db9e16ea4..225008882958 100644 --- a/arch/powerpc/kvm/book3s_xive.c +++ b/arch/powerpc/kvm/book3s_xive.c @@ -1928,7 +1928,7 @@ int kvmppc_xive_set_nr_servers(struct kvmppc_xive *xive, u64 addr) pr_devel("%s nr_servers=%u\n", __func__, nr_servers); - if (!nr_servers || nr_servers > KVM_MAX_VCPU_ID) + if (!nr_servers || nr_servers > KVM_MAX_VCPU_IDS) return -EINVAL; mutex_lock(&xive->lock); diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index b4e6f70b97b9..8ab90ce8738f 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -649,7 +649,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_MAX_VCPUS; break; case KVM_CAP_MAX_VCPU_ID: - r = KVM_MAX_VCPU_ID; + r = KVM_MAX_VCPU_IDS; break; #ifdef CONFIG_PPC_BOOK3S_64 case KVM_CAP_PPC_GET_SMMU_INFO: diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f8f48a7ec577..261b7d857fc0 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -50,7 +50,7 @@ * so ratio of 4 should be enough. */ #define KVM_VCPU_ID_RATIO 4 -#define KVM_MAX_VCPU_ID (KVM_MAX_VCPUS * KVM_VCPU_ID_RATIO) +#define KVM_MAX_VCPU_IDS (KVM_MAX_VCPUS * KVM_VCPU_ID_RATIO) /* memory slots that are not exposed to userspace */ #define KVM_PRIVATE_MEM_SLOTS 3 diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c index 698969e18fe3..3358123be946 100644 --- a/arch/x86/kvm/ioapic.c +++ b/arch/x86/kvm/ioapic.c @@ -96,7 +96,7 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic, static void rtc_irq_eoi_tracking_reset(struct kvm_ioapic *ioapic) { ioapic->rtc_status.pending_eoi = 0; - bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID); + bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_IDS); } static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic); diff --git a/arch/x86/kvm/ioapic.h b/arch/x86/kvm/ioapic.h index 27e61ff3ac3e..e66e620c3bed 100644 --- a/arch/x86/kvm/ioapic.h +++ b/arch/x86/kvm/ioapic.h @@ -39,13 +39,13 @@ struct kvm_vcpu; struct dest_map { /* vcpu bitmap where IRQ has been sent */ - DECLARE_BITMAP(map, KVM_MAX_VCPU_ID); + DECLARE_BITMAP(map, KVM_MAX_VCPU_IDS); /* * Vector sent to a given vcpu, only valid when * the vcpu's bit in map is set */ - u8 vectors[KVM_MAX_VCPU_ID]; + u8 vectors[KVM_MAX_VCPU_IDS]; }; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 28ef14155726..fec43997522b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4070,7 +4070,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_MAX_VCPUS; break; case KVM_CAP_MAX_VCPU_ID: - r = KVM_MAX_VCPU_ID; + r = KVM_MAX_VCPU_IDS; break; case KVM_CAP_PV_MMU: /* obsolete */ r = 0; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 041ca7f15ea4..d2b405170f6e 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -39,8 +39,8 @@ #include <asm/kvm_host.h> #include <linux/kvm_dirty_ring.h> -#ifndef KVM_MAX_VCPU_ID -#define KVM_MAX_VCPU_ID KVM_MAX_VCPUS +#ifndef KVM_MAX_VCPU_IDS +#define KVM_MAX_VCPU_IDS KVM_MAX_VCPUS #endif /* diff --git a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c index 0299cd81b8ba..f968dfd4ee88 100644 --- a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c +++ b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c @@ -53,7 +53,7 @@ int main(int argc, char *argv[]) kvm_max_vcpu_id = kvm_max_vcpus; TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus, - "KVM_MAX_VCPU_ID (%d) must be at least as large as KVM_MAX_VCPUS (%d).", + "KVM_MAX_VCPU_IDS (%d) must be at least as large as KVM_MAX_VCPUS (%d).", kvm_max_vcpu_id, kvm_max_vcpus); test_vcpu_creation(0, kvm_max_vcpus); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 439d3b4cd1a9..62fcbc897e1c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3557,7 +3557,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) struct kvm_vcpu *vcpu; struct page *page; - if (id >= KVM_MAX_VCPU_ID) + if (id >= KVM_MAX_VCPU_IDS) return -EINVAL; mutex_lock(&kvm->lock);
KVM_MAX_VCPU_ID is not specifying the highest allowed vcpu-id, but the number of allowed vcpu-ids. This has already led to confusion, so rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDS to make its semantics more clear Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Juergen Gross <jgross@suse.com> --- Documentation/virt/kvm/devices/xics.rst | 2 +- Documentation/virt/kvm/devices/xive.rst | 2 +- arch/mips/kvm/mips.c | 2 +- arch/powerpc/include/asm/kvm_book3s.h | 2 +- arch/powerpc/include/asm/kvm_host.h | 4 ++-- arch/powerpc/kvm/book3s_xive.c | 2 +- arch/powerpc/kvm/powerpc.c | 2 +- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/ioapic.c | 2 +- arch/x86/kvm/ioapic.h | 4 ++-- arch/x86/kvm/x86.c | 2 +- include/linux/kvm_host.h | 4 ++-- tools/testing/selftests/kvm/kvm_create_max_vcpus.c | 2 +- virt/kvm/kvm_main.c | 2 +- 14 files changed, 17 insertions(+), 17 deletions(-)