| Message ID | 20190317211456.13927-20-jarkko.sakkinen@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Intel SGX1 support | expand |
On Sun, Mar 17, 2019 at 11:14:48PM +0200, Jarkko Sakkinen wrote: > Add VMA callbacks for ptrace() that can be used with debug enclaves. > With debug enclaves data can be read and write the memory word at a time > by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions. > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > --- > arch/x86/kernel/cpu/sgx/encl.c | 97 ++++++++++++++++++++++++++++++++++ > 1 file changed, 97 insertions(+) > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index 1b8874699dd3..5b5fc933ee19 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -256,10 +256,107 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf) > return ret; > } > > +static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page, > + unsigned long addr, void *data) > +{ > + unsigned long offset; > + int ret; > + > + offset = addr & ~PAGE_MASK; > + > + if ((page->desc & SGX_ENCL_PAGE_TCS) && > + offset > offsetof(struct sgx_tcs, gs_limit)) > + return -ECANCELED; > + > + ret = __edbgrd(sgx_epc_addr(page->epc_page) + offset, data); > + if (ret) > + return -EIO; > + > + return 0; > +} > + > +static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page, > + unsigned long addr, void *data) > +{ > + unsigned long offset; > + int ret; > + > + offset = addr & ~PAGE_MASK; > + > + /* Writing anything else than flags will cause #GP */ > + if ((page->desc & SGX_ENCL_PAGE_TCS) && > + offset != offsetof(struct sgx_tcs, flags)) > + return -ECANCELED; > + > + ret = __edbgwr(sgx_epc_addr(page->epc_page) + offset, data); > + if (ret) > + return -EIO; > + > + return 0; > +} > + > +static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr, > + void *buf, int len, int write) > +{ > + struct sgx_encl *encl = vma->vm_private_data; > + struct sgx_encl_page *entry = NULL; > + unsigned long align; > + char data[sizeof(unsigned long)]; > + int offset; > + int cnt; > + int ret = 0; > + int i; > + > + /* If process was forked, VMA is still there but vm_private_data is set > + * to NULL. > + */ > + if (!encl) > + return -EFAULT; > + > + if (!(encl->flags & SGX_ENCL_DEBUG) || > + !(encl->flags & SGX_ENCL_INITIALIZED) || > + (encl->flags & SGX_ENCL_DEAD)) > + return -EFAULT; > + > + for (i = 0; i < len; i += cnt) { > + entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK); Taking a lock indirectly via sgx_encl_reserve_page() and releasing it directly via mutex_unlock() is a bit difficult to follow, having a helper to pair up with sgx_encl_reserve_page() would be more readable. Open coding sgx_encl_reserve_page() would probably be even better since this is the only user AFAICT. All that being said, I prefer the old approach of marking the page RESERVED instead of holding the enclave's lock, even though it was slightly more complex. > + if (IS_ERR(entry)) { > + ret = PTR_ERR(entry); > + break; > + } > + > + align = ALIGN_DOWN(addr + i, sizeof(unsigned long)); > + offset = (addr + i) & (sizeof(unsigned long) - 1); > + cnt = sizeof(unsigned long) - offset; > + cnt = min(cnt, len - i); > + > + ret = sgx_edbgrd(encl, entry, align, data); > + if (ret) > + goto out; > + > + if (write) { > + memcpy(data + offset, buf + i, cnt); > + ret = sgx_edbgwr(encl, entry, align, data); > + if (ret) > + goto out; > + } else > + memcpy(buf + i, data + offset, cnt); > + > +out: > + mutex_unlock(&encl->lock); > + > + if (ret) > + break; > + } > + > + return ret < 0 ? ret : i; > +} > + > const struct vm_operations_struct sgx_vm_ops = { > .close = sgx_vma_close, > .open = sgx_vma_open, > .fault = sgx_vma_fault, > + .access = sgx_vma_access, > }; > EXPORT_SYMBOL_GPL(sgx_vm_ops); > > -- > 2.19.1 >
On Tue, Mar 19, 2019 at 03:22:01PM -0700, Sean Christopherson wrote: > On Sun, Mar 17, 2019 at 11:14:48PM +0200, Jarkko Sakkinen wrote: > > Add VMA callbacks for ptrace() that can be used with debug enclaves. > > With debug enclaves data can be read and write the memory word at a time > > by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions. > > > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > --- > > arch/x86/kernel/cpu/sgx/encl.c | 97 ++++++++++++++++++++++++++++++++++ > > 1 file changed, 97 insertions(+) > > > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > > index 1b8874699dd3..5b5fc933ee19 100644 > > --- a/arch/x86/kernel/cpu/sgx/encl.c > > +++ b/arch/x86/kernel/cpu/sgx/encl.c > > @@ -256,10 +256,107 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf) > > return ret; > > } > > > > +static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page, > > + unsigned long addr, void *data) > > +{ > > + unsigned long offset; > > + int ret; > > + > > + offset = addr & ~PAGE_MASK; > > + > > + if ((page->desc & SGX_ENCL_PAGE_TCS) && > > + offset > offsetof(struct sgx_tcs, gs_limit)) > > + return -ECANCELED; > > + > > + ret = __edbgrd(sgx_epc_addr(page->epc_page) + offset, data); > > + if (ret) > > + return -EIO; > > + > > + return 0; > > +} > > + > > +static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page, > > + unsigned long addr, void *data) > > +{ > > + unsigned long offset; > > + int ret; > > + > > + offset = addr & ~PAGE_MASK; > > + > > + /* Writing anything else than flags will cause #GP */ > > + if ((page->desc & SGX_ENCL_PAGE_TCS) && > > + offset != offsetof(struct sgx_tcs, flags)) > > + return -ECANCELED; > > + > > + ret = __edbgwr(sgx_epc_addr(page->epc_page) + offset, data); > > + if (ret) > > + return -EIO; > > + > > + return 0; > > +} > > + > > +static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr, > > + void *buf, int len, int write) > > +{ > > + struct sgx_encl *encl = vma->vm_private_data; > > + struct sgx_encl_page *entry = NULL; > > + unsigned long align; > > + char data[sizeof(unsigned long)]; > > + int offset; > > + int cnt; > > + int ret = 0; > > + int i; > > + > > + /* If process was forked, VMA is still there but vm_private_data is set > > + * to NULL. > > + */ > > + if (!encl) > > + return -EFAULT; > > + > > + if (!(encl->flags & SGX_ENCL_DEBUG) || > > + !(encl->flags & SGX_ENCL_INITIALIZED) || > > + (encl->flags & SGX_ENCL_DEAD)) > > + return -EFAULT; > > + > > + for (i = 0; i < len; i += cnt) { > > + entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK); > > Taking a lock indirectly via sgx_encl_reserve_page() and releasing it > directly via mutex_unlock() is a bit difficult to follow, having a helper > to pair up with sgx_encl_reserve_page() would be more readable. Open > coding sgx_encl_reserve_page() would probably be even better since this > is the only user AFAICT. > > All that being said, I prefer the old approach of marking the page RESERVED > instead of holding the enclave's lock, even though it was slightly more > complex. For me the big rationale is to minimize the amount of state in the context of this patch set. And this approach should work just fine. /Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 1b8874699dd3..5b5fc933ee19 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -256,10 +256,107 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf) return ret; } +static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page, + unsigned long addr, void *data) +{ + unsigned long offset; + int ret; + + offset = addr & ~PAGE_MASK; + + if ((page->desc & SGX_ENCL_PAGE_TCS) && + offset > offsetof(struct sgx_tcs, gs_limit)) + return -ECANCELED; + + ret = __edbgrd(sgx_epc_addr(page->epc_page) + offset, data); + if (ret) + return -EIO; + + return 0; +} + +static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page, + unsigned long addr, void *data) +{ + unsigned long offset; + int ret; + + offset = addr & ~PAGE_MASK; + + /* Writing anything else than flags will cause #GP */ + if ((page->desc & SGX_ENCL_PAGE_TCS) && + offset != offsetof(struct sgx_tcs, flags)) + return -ECANCELED; + + ret = __edbgwr(sgx_epc_addr(page->epc_page) + offset, data); + if (ret) + return -EIO; + + return 0; +} + +static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr, + void *buf, int len, int write) +{ + struct sgx_encl *encl = vma->vm_private_data; + struct sgx_encl_page *entry = NULL; + unsigned long align; + char data[sizeof(unsigned long)]; + int offset; + int cnt; + int ret = 0; + int i; + + /* If process was forked, VMA is still there but vm_private_data is set + * to NULL. + */ + if (!encl) + return -EFAULT; + + if (!(encl->flags & SGX_ENCL_DEBUG) || + !(encl->flags & SGX_ENCL_INITIALIZED) || + (encl->flags & SGX_ENCL_DEAD)) + return -EFAULT; + + for (i = 0; i < len; i += cnt) { + entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK); + if (IS_ERR(entry)) { + ret = PTR_ERR(entry); + break; + } + + align = ALIGN_DOWN(addr + i, sizeof(unsigned long)); + offset = (addr + i) & (sizeof(unsigned long) - 1); + cnt = sizeof(unsigned long) - offset; + cnt = min(cnt, len - i); + + ret = sgx_edbgrd(encl, entry, align, data); + if (ret) + goto out; + + if (write) { + memcpy(data + offset, buf + i, cnt); + ret = sgx_edbgwr(encl, entry, align, data); + if (ret) + goto out; + } else + memcpy(buf + i, data + offset, cnt); + +out: + mutex_unlock(&encl->lock); + + if (ret) + break; + } + + return ret < 0 ? ret : i; +} + const struct vm_operations_struct sgx_vm_ops = { .close = sgx_vma_close, .open = sgx_vma_open, .fault = sgx_vma_fault, + .access = sgx_vma_access, }; EXPORT_SYMBOL_GPL(sgx_vm_ops);
Add VMA callbacks for ptrace() that can be used with debug enclaves. With debug enclaves data can be read and write the memory word at a time by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions. Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 97 ++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+)