[RFC PATCH v5 6/7] kvmppc: Support reset of secure guest
janani
janani at linux.ibm.com
Wed Jul 10 23:30:21 AEST 2019
On 2019-07-09 05:25, Bharata B Rao wrote:
> Add support for reset of secure guest via a new ioctl KVM_PPC_SVM_OFF.
> This ioctl will be issued by QEMU during reset and includes the
> the following steps:
>
> - Ask UV to terminate the guest via UV_SVM_TERMINATE ucall
> - Unpin the VPA pages so that they can be migrated back to secure
> side when guest becomes secure again. This is required because
> pinned pages can't be migrated.
> - Reinitialize guest's partitioned scoped page tables. These are
> freed when guest become secure (H_SVM_INIT_DONE)
> - Release all HMM pages of the secure guest.
>
> After these steps, guest is ready to issue UV_ESM call once again
> to switch to secure mode.
>
> Signed-off-by: Bharata B Rao <bharata at linux.ibm.com>
> Signed-off-by: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
> [Implementation of uv_svm_terminate() and its call from
> guest shutdown path]
> Signed-off-by: Ram Pai <linuxram at us.ibm.com>
> [Unpinning of VPA pages]
Reviewed-by: Janani Janakiraman <janani at linux.ibm.com>
> ---
> Documentation/virtual/kvm/api.txt | 19 ++++++
> arch/powerpc/include/asm/kvm_book3s_hmm.h | 7 +++
> arch/powerpc/include/asm/kvm_ppc.h | 2 +
> arch/powerpc/include/asm/ultravisor-api.h | 1 +
> arch/powerpc/include/asm/ultravisor.h | 7 +++
> arch/powerpc/kvm/book3s_hv.c | 70 +++++++++++++++++++++++
> arch/powerpc/kvm/book3s_hv_hmm.c | 60 +++++++++++++++++++
> arch/powerpc/kvm/powerpc.c | 12 ++++
> include/uapi/linux/kvm.h | 1 +
> tools/include/uapi/linux/kvm.h | 1 +
> 10 files changed, 180 insertions(+)
>
> diff --git a/Documentation/virtual/kvm/api.txt
> b/Documentation/virtual/kvm/api.txt
> index ba6c42c576dd..c89c24ad86ed 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -4065,6 +4065,25 @@ KVM_ARM_VCPU_FINALIZE call.
> See KVM_ARM_VCPU_INIT for details of vcpu features that require
> finalization
> using this ioctl.
>
> +4.120 KVM_PPC_SVM_OFF
> +
> +Capability: basic
> +Architectures: powerpc
> +Type: vm ioctl
> +Parameters: none
> +Returns: 0 on successful completion,
> +Errors:
> + EINVAL: if ultravisor failed to terminate the secure guest
> + ENOMEM: if hypervisor failed to allocate new radix page tables
> for guest
> +
> +This ioctl is used to turn off the secure mode of the guest or
> transition
> +the guest from secure mode to normal mode. This is invoked when the
> guest
> +is reset. This has no effect if called for a normal guest.
> +
> +This ioctl issues an ultravisor call to terminate the secure guest,
> +unpin the VPA pages, reinitialize guest's partition scoped page
> +tables and releases all the HMM pages that is associated with this
> guest.
> +
> 5. The kvm_run structure
> ------------------------
>
> diff --git a/arch/powerpc/include/asm/kvm_book3s_hmm.h
> b/arch/powerpc/include/asm/kvm_book3s_hmm.h
> index 8c7aacabb2e0..cd2b0f927766 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_hmm.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_hmm.h
> @@ -13,6 +13,8 @@ extern unsigned long kvmppc_h_svm_page_out(struct kvm
> *kvm,
> unsigned long page_shift);
> extern unsigned long kvmppc_h_svm_init_start(struct kvm *kvm);
> extern unsigned long kvmppc_h_svm_init_done(struct kvm *kvm);
> +extern void kvmppc_hmm_free_memslot_pfns(struct kvm *kvm,
> + struct kvm_memslots *slots);
> #else
> static inline unsigned long
> kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gra,
> @@ -37,5 +39,10 @@ static inline unsigned long
> kvmppc_h_svm_init_done(struct kvm *kvm)
> {
> return H_UNSUPPORTED;
> }
> +
> +static inline void kvmppc_hmm_free_memslot_pfns(struct kvm *kvm,
> + struct kvm_memslots *slots)
> +{
> +}
> #endif /* CONFIG_PPC_UV */
> #endif /* __POWERPC_KVM_PPC_HMM_H__ */
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h
> b/arch/powerpc/include/asm/kvm_ppc.h
> index bc892380e6cd..d80ece28d65d 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -188,6 +188,7 @@ extern void
> kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
> extern int kvmppc_switch_mmu_to_hpt(struct kvm *kvm);
> extern int kvmppc_switch_mmu_to_radix(struct kvm *kvm);
> extern void kvmppc_setup_partition_table(struct kvm *kvm);
> +extern int kvmppc_reinit_partition_table(struct kvm *kvm);
>
> extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
> struct kvm_create_spapr_tce_64 *args);
> @@ -332,6 +333,7 @@ struct kvmppc_ops {
> int size);
> int (*store_to_eaddr)(struct kvm_vcpu *vcpu, ulong *eaddr, void *ptr,
> int size);
> + int (*svm_off)(struct kvm *kvm);
> };
>
> extern struct kvmppc_ops *kvmppc_hv_ops;
> diff --git a/arch/powerpc/include/asm/ultravisor-api.h
> b/arch/powerpc/include/asm/ultravisor-api.h
> index 9f5510b55892..c8180427fa01 100644
> --- a/arch/powerpc/include/asm/ultravisor-api.h
> +++ b/arch/powerpc/include/asm/ultravisor-api.h
> @@ -25,5 +25,6 @@
> #define UV_PAGE_IN 0xF128
> #define UV_PAGE_OUT 0xF12C
> #define UV_PAGE_INVAL 0xF138
> +#define UV_SVM_TERMINATE 0xF13C
>
> #endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
> diff --git a/arch/powerpc/include/asm/ultravisor.h
> b/arch/powerpc/include/asm/ultravisor.h
> index f4f674794b35..a5e4516c8ddb 100644
> --- a/arch/powerpc/include/asm/ultravisor.h
> +++ b/arch/powerpc/include/asm/ultravisor.h
> @@ -84,6 +84,13 @@ static inline int uv_page_inval(u64 lpid, u64 gpa,
> u64 page_shift)
>
> return ucall(UV_PAGE_INVAL, retbuf, lpid, gpa, page_shift);
> }
> +
> +static inline int uv_svm_terminate(u64 lpid)
> +{
> + unsigned long retbuf[UCALL_BUFSIZE];
> +
> + return ucall(UV_SVM_TERMINATE, retbuf, lpid);
> +}
> #endif /* !__ASSEMBLY__ */
>
> #endif /* _ASM_POWERPC_ULTRAVISOR_H */
> diff --git a/arch/powerpc/kvm/book3s_hv.c
> b/arch/powerpc/kvm/book3s_hv.c
> index 7cbb5edaed01..41b0fff199d3 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -2437,6 +2437,15 @@ static void unpin_vpa(struct kvm *kvm, struct
> kvmppc_vpa *vpa)
> vpa->dirty);
> }
>
> +static void unpin_vpa_reset(struct kvm *kvm, struct kvmppc_vpa *vpa)
> +{
> + unpin_vpa(kvm, vpa);
> + vpa->gpa = 0;
> + vpa->pinned_addr = NULL;
> + vpa->dirty = false;
> + vpa->update_pending = 0;
> +}
> +
> static void kvmppc_core_vcpu_free_hv(struct kvm_vcpu *vcpu)
> {
> spin_lock(&vcpu->arch.vpa_update_lock);
> @@ -4577,6 +4586,22 @@ void kvmppc_setup_partition_table(struct kvm
> *kvm)
> kvmhv_set_ptbl_entry(kvm->arch.lpid, dw0, dw1);
> }
>
> +/*
> + * Called from KVM_PPC_SVM_OFF ioctl at guest reset time when secure
> + * guest is converted back to normal guest.
> + */
> +int kvmppc_reinit_partition_table(struct kvm *kvm)
> +{
> + int ret;
> +
> + ret = kvmppc_init_vm_radix(kvm);
> + if (ret)
> + return ret;
> +
> + kvmppc_setup_partition_table(kvm);
> + return 0;
> +}
> +
> /*
> * Set up HPT (hashed page table) and RMA (real-mode area).
> * Must be called with kvm->lock held.
> @@ -4956,6 +4981,7 @@ static void kvmppc_core_destroy_vm_hv(struct kvm
> *kvm)
> if (nesting_enabled(kvm))
> kvmhv_release_all_nested(kvm);
> kvm->arch.process_table = 0;
> + uv_svm_terminate(kvm->arch.lpid);
> kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
> }
> kvmppc_free_lpid(kvm->arch.lpid);
> @@ -5397,6 +5423,49 @@ static int kvmhv_store_to_eaddr(struct kvm_vcpu
> *vcpu, ulong *eaddr, void *ptr,
> return rc;
> }
>
> +/*
> + * IOCTL handler to turn off secure mode of guest
> + *
> + * - Issue ucall to terminate the guest on the UV side
> + * - Unpin the VPA pages (Enables these pages to be migrated back
> + * when VM becomes secure again)
> + * - Recreate partition table as the guest is transitioning back to
> + * normal mode
> + * - Release all HMM pages
> + */
> +static int kvmhv_svm_off(struct kvm *kvm)
> +{
> + struct kvm_vcpu *vcpu;
> + int ret = 0;
> + int i;
> +
> + if (kvmppc_is_guest_secure(kvm)) {
> + ret = uv_svm_terminate(kvm->arch.lpid);
> + if (ret != U_SUCCESS) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + spin_lock(&vcpu->arch.vpa_update_lock);
> + unpin_vpa_reset(kvm, &vcpu->arch.dtl);
> + unpin_vpa_reset(kvm, &vcpu->arch.slb_shadow);
> + unpin_vpa_reset(kvm, &vcpu->arch.vpa);
> + spin_unlock(&vcpu->arch.vpa_update_lock);
> + }
> +
> + ret = kvmppc_reinit_partition_table(kvm);
> + if (ret)
> + goto out;
> + kvm->arch.secure_guest = 0;
> + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
> + kvmppc_hmm_free_memslot_pfns(kvm,
> + __kvm_memslots(kvm, i));
> + }
> +out:
> + return ret;
> +}
> +
> static struct kvmppc_ops kvm_ops_hv = {
> .get_sregs = kvm_arch_vcpu_ioctl_get_sregs_hv,
> .set_sregs = kvm_arch_vcpu_ioctl_set_sregs_hv,
> @@ -5439,6 +5508,7 @@ static struct kvmppc_ops kvm_ops_hv = {
> .enable_nested = kvmhv_enable_nested,
> .load_from_eaddr = kvmhv_load_from_eaddr,
> .store_to_eaddr = kvmhv_store_to_eaddr,
> + .svm_off = kvmhv_svm_off,
> };
>
> static int kvm_init_subcore_bitmap(void)
> diff --git a/arch/powerpc/kvm/book3s_hv_hmm.c
> b/arch/powerpc/kvm/book3s_hv_hmm.c
> index 9e6c88de456f..165926c069ba 100644
> --- a/arch/powerpc/kvm/book3s_hv_hmm.c
> +++ b/arch/powerpc/kvm/book3s_hv_hmm.c
> @@ -38,6 +38,8 @@
> #include <linux/kvm_host.h>
> #include <linux/sched/mm.h>
> #include <asm/ultravisor.h>
> +#include <asm/kvm_ppc.h>
> +#include <asm/kvm_book3s.h>
>
> struct kvmppc_hmm_device {
> struct hmm_device *device;
> @@ -98,6 +100,12 @@ unsigned long kvmppc_h_svm_init_done(struct kvm
> *kvm)
> return H_UNSUPPORTED;
>
> kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_DONE;
> + if (kvm_is_radix(kvm)) {
> + pr_info("LPID %d went secure, freeing HV side radix pgtables\n",
> + kvm->arch.lpid);
> + kvmppc_free_radix(kvm);
> + }
> +
> return H_SUCCESS;
> }
>
> @@ -113,6 +121,58 @@ static inline bool kvmppc_is_hmm_pfn(unsigned long
> pfn)
> return !!(pfn & KVMPPC_PFN_HMM);
> }
>
> +/*
> + * Drop HMM pages that we maintain for the secure guest
> + *
> + * We mark the pages to be skipped from UV_PAGE_OUT when there is HMM
> + * fault on these pages. Next we get these pages, force HMM fault,
> + * do fault migration to replace the HMM PTEs from QEMU page tables
> + * with normal PTEs from newly allocated pages.
> + */
> +static void kvmppc_hmm_drop_pages(struct kvm_memory_slot *free,
> struct kvm *kvm)
> +{
> + int i;
> + struct kvmppc_hmm_page_pvt *pvt;
> + unsigned long pfn;
> +
> + for (i = 0; i < free->npages; i++) {
> + unsigned long *rmap = &free->arch.rmap[i];
> + struct page *hmm_page;
> +
> + if (kvmppc_is_hmm_pfn(*rmap)) {
> + hmm_page = pfn_to_page(*rmap & ~KVMPPC_PFN_HMM);
> + pvt = (struct kvmppc_hmm_page_pvt *)
> + hmm_devmem_page_get_drvdata(hmm_page);
> + pvt->skip_page_out = true;
> +
> + pfn = gfn_to_pfn(kvm, pvt->gpa >> PAGE_SHIFT);
> + if (is_error_noslot_pfn(pfn))
> + continue;
> + kvm_release_pfn_clean(pfn);
> + }
> + }
> +}
> +
> +/*
> + * Called from KVM_PPC_SVM_OFF ioctl when secure guest is reset
> + *
> + * UV has already cleaned up the guest, we release any HMM pages that
> + * we maintain
> + */
> +void kvmppc_hmm_free_memslot_pfns(struct kvm *kvm, struct kvm_memslots
> *slots)
> +{
> + struct kvm_memory_slot *memslot;
> + int srcu_idx;
> +
> + if (!slots)
> + return;
> +
> + srcu_idx = srcu_read_lock(&kvm->srcu);
> + kvm_for_each_memslot(memslot, slots)
> + kvmppc_hmm_drop_pages(memslot, kvm);
> + srcu_read_unlock(&kvm->srcu, srcu_idx);
> +}
> +
> /*
> * Get a free HMM PFN from the pool
> *
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 3393b166817a..0c5fae004adf 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -42,6 +42,8 @@
> #include <asm/hvcall.h>
> #include <asm/plpar_wrappers.h>
> #endif
> +#include <asm/ultravisor.h>
> +#include <asm/kvm_host.h>
>
> #include "timing.h"
> #include "irq.h"
> @@ -2423,6 +2425,16 @@ long kvm_arch_vm_ioctl(struct file *filp,
> r = -EFAULT;
> break;
> }
> + case KVM_PPC_SVM_OFF: {
> + struct kvm *kvm = filp->private_data;
> +
> + r = 0;
> + if (!kvm->arch.kvm_ops->svm_off)
> + goto out;
> +
> + r = kvm->arch.kvm_ops->svm_off(kvm);
> + break;
> + }
> default: {
> struct kvm *kvm = filp->private_data;
> r = kvm->arch.kvm_ops->arch_vm_ioctl(filp, ioctl, arg);
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 2fe12b40d503..c1dbdd428025 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1327,6 +1327,7 @@ struct kvm_s390_ucas_mapping {
> #define KVM_PPC_GET_RMMU_INFO _IOW(KVMIO, 0xb0, struct
> kvm_ppc_rmmu_info)
> /* Available with KVM_CAP_PPC_GET_CPU_CHAR */
> #define KVM_PPC_GET_CPU_CHAR _IOR(KVMIO, 0xb1, struct
> kvm_ppc_cpu_char)
> +#define KVM_PPC_SVM_OFF _IO(KVMIO, 0xb2)
>
> /* ioctl for vm fd */
> #define KVM_CREATE_DEVICE _IOWR(KVMIO, 0xe0, struct
> kvm_create_device)
> diff --git a/tools/include/uapi/linux/kvm.h
> b/tools/include/uapi/linux/kvm.h
> index 6d4ea4b6c922..03c89f4a01b2 100644
> --- a/tools/include/uapi/linux/kvm.h
> +++ b/tools/include/uapi/linux/kvm.h
> @@ -1319,6 +1319,7 @@ struct kvm_s390_ucas_mapping {
> #define KVM_PPC_GET_RMMU_INFO _IOW(KVMIO, 0xb0, struct
> kvm_ppc_rmmu_info)
> /* Available with KVM_CAP_PPC_GET_CPU_CHAR */
> #define KVM_PPC_GET_CPU_CHAR _IOR(KVMIO, 0xb1, struct
> kvm_ppc_cpu_char)
> +#define KVM_PPC_SVM_OFF _IO(KVMIO, 0xb2)
>
> /* ioctl for vm fd */
> #define KVM_CREATE_DEVICE _IOWR(KVMIO, 0xe0, struct
> kvm_create_device)
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