| Message ID | 20190910082946.7849-4-bharata@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kvmppc: Driver to manage pages of secure guest | expand |
> A secure guest will share some of its pages with hypervisor (Eg. virtio > bounce buffers etc). Support sharing of pages between hypervisor and > ultravisor. A brief note about what a shared page is would help (a page belonging to the SVM but in normal memory and with decrypted contents)? Either here or in the function header of kvmppc_h_svm_page_in() where we handle shared pages. > > Once a secure page is converted to shared page, the device page is Maybe useful to add "the device page (representing the secure page") is ... > unmapped from the HV side page tables. > > Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> > --- > arch/powerpc/include/asm/hvcall.h | 3 ++ > arch/powerpc/kvm/book3s_hv_uvmem.c | 65 ++++++++++++++++++++++++++++-- > 2 files changed, 65 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h > index 2595d0144958..4e98dd992bd1 100644 > --- a/arch/powerpc/include/asm/hvcall.h > +++ b/arch/powerpc/include/asm/hvcall.h > @@ -342,6 +342,9 @@ > #define H_TLB_INVALIDATE 0xF808 > #define H_COPY_TOFROM_GUEST 0xF80C > > +/* Flags for H_SVM_PAGE_IN */ > +#define H_PAGE_IN_SHARED 0x1 > + > /* Platform-specific hcalls used by the Ultravisor */ > #define H_SVM_PAGE_IN 0xEF00 > #define H_SVM_PAGE_OUT 0xEF04 > diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c > index a1eccb065ba9..bcecb643a730 100644 > --- a/arch/powerpc/kvm/book3s_hv_uvmem.c > +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c > @@ -46,6 +46,7 @@ struct kvmppc_uvmem_page_pvt { > unsigned long *rmap; > unsigned int lpid; > unsigned long gpa; > + bool skip_page_out; > }; > > /* > @@ -159,6 +160,53 @@ kvmppc_svm_page_in(struct vm_area_struct *vma, unsigned long start, > return ret; > } > > +/* > + * Shares the page with HV, thus making it a normal page. > + * > + * - If the page is already secure, then provision a new page and share > + * - If the page is a normal page, share the existing page > + * > + * In the former case, uses the dev_pagemap_ops migrate_to_ram handler > + * to unmap the device page from QEMU's page tables. > + */ > +static unsigned long > +kvmppc_share_page(struct kvm *kvm, unsigned long gpa, unsigned long page_shift) > +{ > + > + int ret = H_PARAMETER; > + struct page *uvmem_page; > + struct kvmppc_uvmem_page_pvt *pvt; > + unsigned long pfn; > + unsigned long *rmap; > + struct kvm_memory_slot *slot; > + unsigned long gfn = gpa >> page_shift; > + int srcu_idx; > + > + srcu_idx = srcu_read_lock(&kvm->srcu); > + slot = gfn_to_memslot(kvm, gfn); > + if (!slot) > + goto out; > + > + rmap = &slot->arch.rmap[gfn - slot->base_gfn]; > + if (kvmppc_rmap_type(rmap) == KVMPPC_RMAP_UVMEM_PFN) { > + uvmem_page = pfn_to_page(*rmap & ~KVMPPC_RMAP_UVMEM_PFN); > + pvt = (struct kvmppc_uvmem_page_pvt *) > + uvmem_page->zone_device_data; > + pvt->skip_page_out = true; > + } > + > + pfn = gfn_to_pfn(kvm, gfn); > + if (is_error_noslot_pfn(pfn)) > + goto out; > + > + if (!uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, page_shift)) > + ret = H_SUCCESS; > + kvm_release_pfn_clean(pfn); > +out: > + srcu_read_unlock(&kvm->srcu, srcu_idx); > + return ret; > +} > + > /* > * H_SVM_PAGE_IN: Move page from normal memory to secure memory. Would help to mention/remind here what a shared page is. > */ > @@ -177,9 +225,12 @@ kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa, > if (page_shift != PAGE_SHIFT) > return H_P3; > > - if (flags) > + if (flags & ~H_PAGE_IN_SHARED) > return H_P2; > > + if (flags & H_PAGE_IN_SHARED) > + return kvmppc_share_page(kvm, gpa, page_shift); > + > ret = H_PARAMETER; > srcu_idx = srcu_read_lock(&kvm->srcu); > down_read(&kvm->mm->mmap_sem); > @@ -252,8 +303,16 @@ kvmppc_svm_page_out(struct vm_area_struct *vma, unsigned long start, > pvt = spage->zone_device_data; > pfn = page_to_pfn(dpage); > > - ret = uv_page_out(pvt->lpid, pfn << page_shift, pvt->gpa, 0, > - page_shift); > + /* > + * This function is used in two cases: > + * - When HV touches a secure page, for which we do UV_PAGE_OUT > + * - When a secure page is converted to shared page, we touch > + * the page to essentially unmap the device page. In this > + * case we skip page-out. > + */ > + if (!pvt->skip_page_out) > + ret = uv_page_out(pvt->lpid, pfn << page_shift, pvt->gpa, 0, > + page_shift); > > if (ret == U_SUCCESS) > *mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED; > -- > 2.21.0
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 2595d0144958..4e98dd992bd1 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -342,6 +342,9 @@ #define H_TLB_INVALIDATE 0xF808 #define H_COPY_TOFROM_GUEST 0xF80C +/* Flags for H_SVM_PAGE_IN */ +#define H_PAGE_IN_SHARED 0x1 + /* Platform-specific hcalls used by the Ultravisor */ #define H_SVM_PAGE_IN 0xEF00 #define H_SVM_PAGE_OUT 0xEF04 diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index a1eccb065ba9..bcecb643a730 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -46,6 +46,7 @@ struct kvmppc_uvmem_page_pvt { unsigned long *rmap; unsigned int lpid; unsigned long gpa; + bool skip_page_out; }; /* @@ -159,6 +160,53 @@ kvmppc_svm_page_in(struct vm_area_struct *vma, unsigned long start, return ret; } +/* + * Shares the page with HV, thus making it a normal page. + * + * - If the page is already secure, then provision a new page and share + * - If the page is a normal page, share the existing page + * + * In the former case, uses the dev_pagemap_ops migrate_to_ram handler + * to unmap the device page from QEMU's page tables. + */ +static unsigned long +kvmppc_share_page(struct kvm *kvm, unsigned long gpa, unsigned long page_shift) +{ + + int ret = H_PARAMETER; + struct page *uvmem_page; + struct kvmppc_uvmem_page_pvt *pvt; + unsigned long pfn; + unsigned long *rmap; + struct kvm_memory_slot *slot; + unsigned long gfn = gpa >> page_shift; + int srcu_idx; + + srcu_idx = srcu_read_lock(&kvm->srcu); + slot = gfn_to_memslot(kvm, gfn); + if (!slot) + goto out; + + rmap = &slot->arch.rmap[gfn - slot->base_gfn]; + if (kvmppc_rmap_type(rmap) == KVMPPC_RMAP_UVMEM_PFN) { + uvmem_page = pfn_to_page(*rmap & ~KVMPPC_RMAP_UVMEM_PFN); + pvt = (struct kvmppc_uvmem_page_pvt *) + uvmem_page->zone_device_data; + pvt->skip_page_out = true; + } + + pfn = gfn_to_pfn(kvm, gfn); + if (is_error_noslot_pfn(pfn)) + goto out; + + if (!uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, page_shift)) + ret = H_SUCCESS; + kvm_release_pfn_clean(pfn); +out: + srcu_read_unlock(&kvm->srcu, srcu_idx); + return ret; +} + /* * H_SVM_PAGE_IN: Move page from normal memory to secure memory. */ @@ -177,9 +225,12 @@ kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa, if (page_shift != PAGE_SHIFT) return H_P3; - if (flags) + if (flags & ~H_PAGE_IN_SHARED) return H_P2; + if (flags & H_PAGE_IN_SHARED) + return kvmppc_share_page(kvm, gpa, page_shift); + ret = H_PARAMETER; srcu_idx = srcu_read_lock(&kvm->srcu); down_read(&kvm->mm->mmap_sem); @@ -252,8 +303,16 @@ kvmppc_svm_page_out(struct vm_area_struct *vma, unsigned long start, pvt = spage->zone_device_data; pfn = page_to_pfn(dpage); - ret = uv_page_out(pvt->lpid, pfn << page_shift, pvt->gpa, 0, - page_shift); + /* + * This function is used in two cases: + * - When HV touches a secure page, for which we do UV_PAGE_OUT + * - When a secure page is converted to shared page, we touch + * the page to essentially unmap the device page. In this + * case we skip page-out. + */ + if (!pvt->skip_page_out) + ret = uv_page_out(pvt->lpid, pfn << page_shift, pvt->gpa, 0, + page_shift); if (ret == U_SUCCESS) *mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;
A secure guest will share some of its pages with hypervisor (Eg. virtio bounce buffers etc). Support sharing of pages between hypervisor and ultravisor. Once a secure page is converted to shared page, the device page is unmapped from the HV side page tables. Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> --- arch/powerpc/include/asm/hvcall.h | 3 ++ arch/powerpc/kvm/book3s_hv_uvmem.c | 65 ++++++++++++++++++++++++++++-- 2 files changed, 65 insertions(+), 3 deletions(-)