| Message ID | 20190709102545.9187-3-bharata@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kvmppc: HMM driver to manage pages of secure guest | expand |
On 2019-07-09 05:25, Bharata B Rao wrote: > A secure guest will share some of its pages with hypervisor (Eg. virtio > bounce buffers etc). Support shared pages in HMM driver. > > Once a secure page is converted to shared page, HMM driver will stop > tracking that page. > > Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Reviewed-by: Janani Janakiraman <janani@linux.ibm.com> > --- > arch/powerpc/include/asm/hvcall.h | 3 ++ > arch/powerpc/kvm/book3s_hv_hmm.c | 66 +++++++++++++++++++++++++++++-- > 2 files changed, 66 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/hvcall.h > b/arch/powerpc/include/asm/hvcall.h > index 2f6b952deb0f..05b8536f6653 100644 > --- a/arch/powerpc/include/asm/hvcall.h > +++ b/arch/powerpc/include/asm/hvcall.h > @@ -337,6 +337,9 @@ > #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_hmm.c > b/arch/powerpc/kvm/book3s_hv_hmm.c > index cd34323888b6..36562b382e70 100644 > --- a/arch/powerpc/kvm/book3s_hv_hmm.c > +++ b/arch/powerpc/kvm/book3s_hv_hmm.c > @@ -52,6 +52,7 @@ struct kvmppc_hmm_page_pvt { > unsigned long *rmap; > unsigned int lpid; > unsigned long gpa; > + bool skip_page_out; > }; > > struct kvmppc_hmm_migrate_args { > @@ -215,6 +216,53 @@ static const struct migrate_vma_ops > kvmppc_hmm_migrate_ops = { > .finalize_and_map = kvmppc_hmm_migrate_finalize_and_map, > }; > > +/* > + * 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 HMM fault handler to release the HMM > page. > + */ > +static unsigned long > +kvmppc_share_page(struct kvm *kvm, unsigned long gpa, unsigned long > page_shift) > +{ > + > + int ret; > + struct page *hmm_page; > + struct kvmppc_hmm_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) { > + srcu_read_unlock(&kvm->srcu, srcu_idx); > + return H_PARAMETER; > + } > + rmap = &slot->arch.rmap[gfn - slot->base_gfn]; > + srcu_read_unlock(&kvm->srcu, srcu_idx); > + > + 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, gpa >> page_shift); > + if (is_error_noslot_pfn(pfn)) > + return H_PARAMETER; > + > + ret = uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, > page_shift); > + kvm_release_pfn_clean(pfn); > + > + return (ret == U_SUCCESS) ? H_SUCCESS : H_PARAMETER; > +} > + > /* > * Move page from normal memory to secure memory. > */ > @@ -235,9 +283,12 @@ 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); > + > down_read(&kvm->mm->mmap_sem); > srcu_idx = srcu_read_lock(&kvm->srcu); > slot = gfn_to_memslot(kvm, gfn); > @@ -299,8 +350,17 @@ kvmppc_hmm_fault_migrate_alloc_and_copy(struct > vm_area_struct *vma, > hmm_devmem_page_get_drvdata(spage); > > pfn = page_to_pfn(dpage); > - ret = uv_page_out(pvt->lpid, pfn << PAGE_SHIFT, > - pvt->gpa, 0, PAGE_SHIFT); > + > + /* > + * This same alloc_and_copy() callback is used in two cases: > + * - When HV touches a secure page, for which we do page-out > + * - When a secure page is converted to shared page, we touch > + * the page to essentially discard the HMM 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) > *dst_pfn = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED; > }
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 2f6b952deb0f..05b8536f6653 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -337,6 +337,9 @@ #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_hmm.c b/arch/powerpc/kvm/book3s_hv_hmm.c index cd34323888b6..36562b382e70 100644 --- a/arch/powerpc/kvm/book3s_hv_hmm.c +++ b/arch/powerpc/kvm/book3s_hv_hmm.c @@ -52,6 +52,7 @@ struct kvmppc_hmm_page_pvt { unsigned long *rmap; unsigned int lpid; unsigned long gpa; + bool skip_page_out; }; struct kvmppc_hmm_migrate_args { @@ -215,6 +216,53 @@ static const struct migrate_vma_ops kvmppc_hmm_migrate_ops = { .finalize_and_map = kvmppc_hmm_migrate_finalize_and_map, }; +/* + * 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 HMM fault handler to release the HMM page. + */ +static unsigned long +kvmppc_share_page(struct kvm *kvm, unsigned long gpa, unsigned long page_shift) +{ + + int ret; + struct page *hmm_page; + struct kvmppc_hmm_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) { + srcu_read_unlock(&kvm->srcu, srcu_idx); + return H_PARAMETER; + } + rmap = &slot->arch.rmap[gfn - slot->base_gfn]; + srcu_read_unlock(&kvm->srcu, srcu_idx); + + 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, gpa >> page_shift); + if (is_error_noslot_pfn(pfn)) + return H_PARAMETER; + + ret = uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, page_shift); + kvm_release_pfn_clean(pfn); + + return (ret == U_SUCCESS) ? H_SUCCESS : H_PARAMETER; +} + /* * Move page from normal memory to secure memory. */ @@ -235,9 +283,12 @@ 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); + down_read(&kvm->mm->mmap_sem); srcu_idx = srcu_read_lock(&kvm->srcu); slot = gfn_to_memslot(kvm, gfn); @@ -299,8 +350,17 @@ kvmppc_hmm_fault_migrate_alloc_and_copy(struct vm_area_struct *vma, hmm_devmem_page_get_drvdata(spage); pfn = page_to_pfn(dpage); - ret = uv_page_out(pvt->lpid, pfn << PAGE_SHIFT, - pvt->gpa, 0, PAGE_SHIFT); + + /* + * This same alloc_and_copy() callback is used in two cases: + * - When HV touches a secure page, for which we do page-out + * - When a secure page is converted to shared page, we touch + * the page to essentially discard the HMM 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) *dst_pfn = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED; }
A secure guest will share some of its pages with hypervisor (Eg. virtio bounce buffers etc). Support shared pages in HMM driver. Once a secure page is converted to shared page, HMM driver will stop tracking that page. Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> --- arch/powerpc/include/asm/hvcall.h | 3 ++ arch/powerpc/kvm/book3s_hv_hmm.c | 66 +++++++++++++++++++++++++++++-- 2 files changed, 66 insertions(+), 3 deletions(-)