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[81.97.203.96]) by smtp.gmail.com with ESMTPSA id n1-20020a05600c4f8100b003d96b8e9bcasm46690271wmq.32.2023.01.03.10.13.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Jan 2023 10:13:04 -0800 (PST) Date: Tue, 3 Jan 2023 18:13:02 +0000 From: "Dr. David Alan Gilbert" To: David Woodhouse Cc: qemu-devel@nongnu.org, Paolo Bonzini , Paul Durrant , Joao Martins , Ankur Arora , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Thomas Huth , Alex =?iso-8859-1?Q?Benn=E9e?= , Juan Quintela , Claudio Fontana , Julien Grall Subject: Re: [RFC PATCH v5 21/52] i386/xen: handle VCPUOP_register_vcpu_info Message-ID: References: <20221230121235.1282915-1-dwmw2@infradead.org> <20221230121235.1282915-22-dwmw2@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221230121235.1282915-22-dwmw2@infradead.org> User-Agent: Mutt/2.2.9 (2022-11-12) Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org * David Woodhouse (dwmw2@infradead.org) wrote: > From: Joao Martins > > Handle the hypercall to set a per vcpu info, and also wire up the default > vcpu_info in the shared_info page for the first 32 vCPUs. > > To avoid deadlock within KVM a vCPU thread must set its *own* vcpu_info > rather than it being set from the context in which the hypercall is > invoked. > > Add the vcpu_info (and default) GPA to the vmstate_x86_cpu for migration, > and restore it in kvm_arch_put_registers() appropriately. > > Signed-off-by: Joao Martins > Signed-off-by: David Woodhouse > --- > target/i386/cpu.h | 2 + > target/i386/kvm/kvm.c | 17 ++++ > target/i386/kvm/trace-events | 1 + > target/i386/kvm/xen-emu.c | 152 ++++++++++++++++++++++++++++++++++- > target/i386/kvm/xen-emu.h | 2 + > target/i386/machine.c | 19 +++++ > 6 files changed, 190 insertions(+), 3 deletions(-) > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index c6c57baed5..109b2e5669 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -1788,6 +1788,8 @@ typedef struct CPUArchState { > #endif > #if defined(CONFIG_KVM) > struct kvm_nested_state *nested_state; > + uint64_t xen_vcpu_info_gpa; > + uint64_t xen_vcpu_info_default_gpa; > #endif > #if defined(CONFIG_HVF) > HVFX86LazyFlags hvf_lflags; > diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > index f365e56fcc..52d69e87e7 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -4734,6 +4734,15 @@ int kvm_arch_put_registers(CPUState *cpu, int level) > kvm_arch_set_tsc_khz(cpu); > } > > +#ifdef CONFIG_XEN_EMU > + if (xen_mode == XEN_EMULATE && level == KVM_PUT_FULL_STATE) { > + ret = kvm_put_xen_state(cpu); > + if (ret < 0) { > + return ret; > + } > + } > +#endif > + > ret = kvm_getput_regs(x86_cpu, 1); > if (ret < 0) { > return ret; > @@ -4833,6 +4842,14 @@ int kvm_arch_get_registers(CPUState *cs) > if (ret < 0) { > goto out; > } > +#ifdef CONFIG_XEN_EMU > + if (xen_mode == XEN_EMULATE) { > + ret = kvm_get_xen_state(cs); > + if (ret < 0) { > + goto out; > + } > + } > +#endif > ret = 0; > out: > cpu_sync_bndcs_hflags(&cpu->env); > diff --git a/target/i386/kvm/trace-events b/target/i386/kvm/trace-events > index 0a47c26e80..14e54dfca5 100644 > --- a/target/i386/kvm/trace-events > +++ b/target/i386/kvm/trace-events > @@ -9,3 +9,4 @@ kvm_x86_update_msi_routes(int num) "Updated %d MSI routes" > # xen-emu.c > kvm_xen_hypercall(int cpu, uint8_t cpl, uint64_t input, uint64_t a0, uint64_t a1, uint64_t a2, uint64_t ret) "xen_hypercall: cpu %d cpl %d input %" PRIu64 " a0 0x%" PRIx64 " a1 0x%" PRIx64 " a2 0x%" PRIx64" ret 0x%" PRIx64 > kvm_xen_set_shared_info(uint64_t gfn) "shared info at gfn 0x%" PRIx64 > +kvm_xen_set_vcpu_attr(int cpu, int type, uint64_t gpa) "vcpu attr cpu %d type %d gpa 0x%" PRIx64 > diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c > index 0e9ae481d8..aa06588c07 100644 > --- a/target/i386/kvm/xen-emu.c > +++ b/target/i386/kvm/xen-emu.c > @@ -120,6 +120,8 @@ int kvm_xen_init(KVMState *s, uint32_t hypercall_msr) > > int kvm_xen_init_vcpu(CPUState *cs) > { > + X86CPU *cpu = X86_CPU(cs); > + CPUX86State *env = &cpu->env; > int err; > > /* > @@ -143,6 +145,9 @@ int kvm_xen_init_vcpu(CPUState *cs) > } > } > > + env->xen_vcpu_info_gpa = INVALID_GPA; > + env->xen_vcpu_info_default_gpa = INVALID_GPA; > + > return 0; > } > > @@ -188,10 +193,58 @@ static bool kvm_xen_hcall_xen_version(struct kvm_xen_exit *exit, X86CPU *cpu, > return true; > } > > +static int kvm_xen_set_vcpu_attr(CPUState *cs, uint16_t type, uint64_t gpa) > +{ > + struct kvm_xen_vcpu_attr xhsi; > + > + xhsi.type = type; > + xhsi.u.gpa = gpa; > + > + trace_kvm_xen_set_vcpu_attr(cs->cpu_index, type, gpa); > + > + return kvm_vcpu_ioctl(cs, KVM_XEN_VCPU_SET_ATTR, &xhsi); > +} > + > +static void do_set_vcpu_info_default_gpa(CPUState *cs, run_on_cpu_data data) > +{ > + X86CPU *cpu = X86_CPU(cs); > + CPUX86State *env = &cpu->env; > + > + env->xen_vcpu_info_default_gpa = data.host_ulong; > + > + /* Changing the default does nothing if a vcpu_info was explicitly set. */ > + if (env->xen_vcpu_info_gpa == INVALID_GPA) { > + kvm_xen_set_vcpu_attr(cs, KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO, > + env->xen_vcpu_info_default_gpa); > + } > +} > + > +static void do_set_vcpu_info_gpa(CPUState *cs, run_on_cpu_data data) > +{ > + X86CPU *cpu = X86_CPU(cs); > + CPUX86State *env = &cpu->env; > + > + env->xen_vcpu_info_gpa = data.host_ulong; > + > + kvm_xen_set_vcpu_attr(cs, KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO, > + env->xen_vcpu_info_gpa); > +} > + > +static void do_vcpu_soft_reset(CPUState *cs, run_on_cpu_data data) > +{ > + X86CPU *cpu = X86_CPU(cs); > + CPUX86State *env = &cpu->env; > + > + env->xen_vcpu_info_gpa = INVALID_GPA; > + env->xen_vcpu_info_default_gpa = INVALID_GPA; > + > + kvm_xen_set_vcpu_attr(cs, KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO, INVALID_GPA); > +} > + > static int xen_set_shared_info(uint64_t gfn) > { > uint64_t gpa = gfn << TARGET_PAGE_BITS; > - int err; > + int i, err; > > /* > * The xen_overlay device tells KVM about it too, since it had to > @@ -206,6 +259,15 @@ static int xen_set_shared_info(uint64_t gfn) > > trace_kvm_xen_set_shared_info(gfn); > > + for (i = 0; i < XEN_LEGACY_MAX_VCPUS; i++) { > + CPUState *cpu = qemu_get_cpu(i); > + if (cpu) { > + async_run_on_cpu(cpu, do_set_vcpu_info_default_gpa, > + RUN_ON_CPU_HOST_ULONG(gpa)); > + } > + gpa += sizeof(vcpu_info_t); > + } > + > return err; > } > > @@ -363,15 +425,43 @@ static bool kvm_xen_hcall_hvm_op(struct kvm_xen_exit *exit, X86CPU *cpu, > } > } > > +static int vcpuop_register_vcpu_info(CPUState *cs, CPUState *target, > + uint64_t arg) > +{ > + struct vcpu_register_vcpu_info rvi; > + uint64_t gpa; > + > + /* No need for 32/64 compat handling */ > + qemu_build_assert(sizeof(rvi) == 16); > + qemu_build_assert(sizeof(struct vcpu_info) == 64); > + > + if (!target) { > + return -ENOENT; > + } > + > + if (kvm_copy_from_gva(cs, arg, &rvi, sizeof(rvi))) { > + return -EFAULT; > + } > + > + if (rvi.offset > TARGET_PAGE_SIZE - sizeof(struct vcpu_info)) { > + return -EINVAL; > + } > + > + gpa = ((rvi.mfn << TARGET_PAGE_BITS) + rvi.offset); > + async_run_on_cpu(target, do_set_vcpu_info_gpa, RUN_ON_CPU_HOST_ULONG(gpa)); > + return 0; > +} > + > static bool kvm_xen_hcall_vcpu_op(struct kvm_xen_exit *exit, X86CPU *cpu, > int cmd, int vcpu_id, uint64_t arg) > { > + CPUState *dest = qemu_get_cpu(vcpu_id); > + CPUState *cs = CPU(cpu); > int err; > > switch (cmd) { > case VCPUOP_register_vcpu_info: > - /* no vcpu info placement for now */ > - err = -ENOSYS; > + err = vcpuop_register_vcpu_info(cs, dest, arg); > break; > > default: > @@ -384,8 +474,13 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_xen_exit *exit, X86CPU *cpu, > > static int kvm_xen_soft_reset(void) > { > + CPUState *cpu; > int err; > > + CPU_FOREACH(cpu) { > + async_run_on_cpu(cpu, do_vcpu_soft_reset, RUN_ON_CPU_NULL); > + } > + > err = xen_overlay_map_shinfo_page(INVALID_GFN); > if (err) { > return err; > @@ -531,3 +626,54 @@ int kvm_xen_handle_exit(X86CPU *cpu, struct kvm_xen_exit *exit) > exit->u.hcall.result); > return 0; > } > + > +int kvm_put_xen_state(CPUState *cs) > +{ > + X86CPU *cpu = X86_CPU(cs); > + CPUX86State *env = &cpu->env; > + uint64_t gpa; > + int ret; > + > + gpa = env->xen_vcpu_info_gpa; > + if (gpa == INVALID_GPA) { > + gpa = env->xen_vcpu_info_default_gpa; > + } > + > + if (gpa != INVALID_GPA) { > + ret = kvm_xen_set_vcpu_attr(cs, KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO, gpa); > + if (ret < 0) { > + return ret; > + } > + } > + > + return 0; > +} > + > +int kvm_get_xen_state(CPUState *cs) > +{ > + X86CPU *cpu = X86_CPU(cs); > + CPUX86State *env = &cpu->env; > + uint64_t gpa; > + > + /* > + * The kernel does not mark vcpu_info as dirty when it delivers interrupts > + * to it. It's up to userspace to *assume* that any page shared thus is > + * always considered dirty. The shared_info page is different since it's > + * an overlay and migrated separately anyway. > + */ > + gpa = env->xen_vcpu_info_gpa; > + if (gpa == INVALID_GPA) { > + gpa = env->xen_vcpu_info_default_gpa; > + } > + if (gpa != INVALID_GPA) { > + MemoryRegionSection mrs = memory_region_find(get_system_memory(), > + gpa, > + sizeof(struct vcpu_info)); > + if (mrs.mr && mrs.size >= sizeof(struct vcpu_info)) { > + memory_region_set_dirty(mrs.mr, mrs.offset_within_region, > + sizeof(struct vcpu_info)); > + } > + } > + > + return 0; > +} > diff --git a/target/i386/kvm/xen-emu.h b/target/i386/kvm/xen-emu.h > index 21faf6bf38..452605699a 100644 > --- a/target/i386/kvm/xen-emu.h > +++ b/target/i386/kvm/xen-emu.h > @@ -26,5 +26,7 @@ > int kvm_xen_init(KVMState *s, uint32_t hypercall_msr); > int kvm_xen_init_vcpu(CPUState *cs); > int kvm_xen_handle_exit(X86CPU *cpu, struct kvm_xen_exit *exit); > +int kvm_put_xen_state(CPUState *cs); > +int kvm_get_xen_state(CPUState *cs); > > #endif /* QEMU_I386_KVM_XEN_EMU_H */ > diff --git a/target/i386/machine.c b/target/i386/machine.c > index 310b125235..1215e616c8 100644 > --- a/target/i386/machine.c > +++ b/target/i386/machine.c > @@ -6,8 +6,10 @@ > #include "kvm/hyperv.h" > #include "hw/i386/x86.h" > #include "kvm/kvm_i386.h" > +#include "hw/xen/xen.h" > > #include "sysemu/kvm.h" > +#include "sysemu/kvm_xen.h" > #include "sysemu/tcg.h" > > #include "qemu/error-report.h" > @@ -1257,6 +1259,22 @@ static const VMStateDescription vmstate_nested_state = { > } > }; > > +static bool xen_vcpu_needed(void *opaque) > +{ > + return (xen_mode == XEN_EMULATE); > +} > + > +static const VMStateDescription vmstate_xen_vcpu = { > + .name = "cpu/xen_vcpu", > + .version_id = 1, > + .minimum_version_id = 1, > + .needed = xen_vcpu_needed, > + .fields = (VMStateField[]) { > + VMSTATE_UINT64(env.xen_vcpu_info_gpa, X86CPU), > + VMSTATE_UINT64(env.xen_vcpu_info_default_gpa, X86CPU), > + VMSTATE_END_OF_LIST() > + } > +}; > #endif > > static bool mcg_ext_ctl_needed(void *opaque) > @@ -1716,6 +1734,7 @@ const VMStateDescription vmstate_x86_cpu = { > #endif > #ifdef CONFIG_KVM > &vmstate_nested_state, > + &vmstate_xen_vcpu, Yep, that shoudln't break anything as long as xen_vcpu_needed is false, so yeh, OK from migration. Dave > #endif > &vmstate_msr_tsx_ctrl, > &vmstate_msr_intel_sgx, > -- > 2.35.3 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK