[PATCH 04/18] KVM: x86: hyper-v: Introduce VTL awareness to Hyper-V's PV-IPIs
From: Nicolas Saenz Julienne <hidden>
Date: 2024-06-09 15:52:44
Also in:
kvm, linux-arch, linux-doc, linux-trace-kernel, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), kvm x86 hyper-v (kvm/hyper-v), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Vitaly Kuznetsov, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
HvCallSendSyntheticClusterIpi and HvCallSendSyntheticClusterIpiEx allow sending VTL-aware IPIs. Honour the hcall by exiting to user-space upon receiving a request with a valid VTL target. This behaviour is only available if the VSM CPUID flag is available and exposed to the guest. It doesn't introduce a behaviour change otherwise. User-space is accountable for the correct processing of the PV-IPI before resuming execution. Signed-off-by: Nicolas Saenz Julienne <redacted> --- arch/x86/kvm/hyperv.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 42f44546fe79c..d00baf3ffb165 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c@@ -2217,16 +2217,20 @@ static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector, static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) { + bool vsm_enabled = kvm_hv_cpuid_vsm_enabled(vcpu); struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); u64 *sparse_banks = hv_vcpu->sparse_banks; struct kvm *kvm = vcpu->kvm; struct hv_send_ipi_ex send_ipi_ex; struct hv_send_ipi send_ipi; + union hv_input_vtl *in_vtl; u64 valid_bank_mask; + int rsvd_shift; u32 vector; bool all_cpus; if (hc->code == HVCALL_SEND_IPI) { + in_vtl = &send_ipi.in_vtl; if (!hc->fast) { if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi, sizeof(send_ipi))))
@@ -2235,16 +2239,22 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) vector = send_ipi.vector; } else { /* 'reserved' part of hv_send_ipi should be 0 */ - if (unlikely(hc->ingpa >> 32 != 0)) + rsvd_shift = vsm_enabled ? 40 : 32; + if (unlikely(hc->ingpa >> rsvd_shift != 0)) return HV_STATUS_INVALID_HYPERCALL_INPUT; + in_vtl->as_uint8 = (u8)(hc->ingpa >> 32); sparse_banks[0] = hc->outgpa; vector = (u32)hc->ingpa; } all_cpus = false; valid_bank_mask = BIT_ULL(0); + if (in_vtl->use_target_vtl) + return -ENODEV; + trace_kvm_hv_send_ipi(vector, sparse_banks[0]); } else { + in_vtl = &send_ipi_ex.in_vtl; if (!hc->fast) { if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi_ex, sizeof(send_ipi_ex))))
@@ -2253,8 +2263,12 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) send_ipi_ex.vector = (u32)hc->ingpa; send_ipi_ex.vp_set.format = hc->outgpa; send_ipi_ex.vp_set.valid_bank_mask = sse128_lo(hc->xmm[0]); + in_vtl->as_uint8 = (u8)(hc->ingpa >> 32); } + if (vsm_enabled && in_vtl->use_target_vtl) + return -ENODEV; + trace_kvm_hv_send_ipi_ex(send_ipi_ex.vector, send_ipi_ex.vp_set.format, send_ipi_ex.vp_set.valid_bank_mask);
@@ -2682,6 +2696,9 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) break; } ret = kvm_hv_send_ipi(vcpu, &hc); + /* VTL-enabled ipi, let user-space handle it */ + if (ret == -ENODEV) + goto hypercall_userspace_exit; break; case HVCALL_POST_DEBUG_DATA: case HVCALL_RETRIEVE_DEBUG_DATA:
--
2.40.1