diff options
| -rw-r--r-- | arch/s390/include/asm/uv.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/uv.c | 55 | ||||
| -rw-r--r-- | arch/s390/mm/fault.c | 10 |
3 files changed, 66 insertions, 0 deletions
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index 18fe04c8547e..be3ef9dd6972 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -426,6 +426,7 @@ static inline int is_prot_virt_host(void) } int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb); +int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr); int uv_destroy_owned_page(unsigned long paddr); int uv_convert_from_secure(unsigned long paddr); int uv_convert_owned_from_secure(unsigned long paddr); diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index c13d5a7b71f0..4c91a3dbc05b 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -334,6 +334,61 @@ int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr) } EXPORT_SYMBOL_GPL(gmap_convert_to_secure); +/** + * gmap_destroy_page - Destroy a guest page. + * @gmap: the gmap of the guest + * @gaddr: the guest address to destroy + * + * An attempt will be made to destroy the given guest page. If the attempt + * fails, an attempt is made to export the page. If both attempts fail, an + * appropriate error is returned. + */ +int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr) +{ + struct vm_area_struct *vma; + unsigned long uaddr; + struct page *page; + int rc; + + rc = -EFAULT; + mmap_read_lock(gmap->mm); + + uaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(uaddr)) + goto out; + vma = vma_lookup(gmap->mm, uaddr); + if (!vma) + goto out; + /* + * Huge pages should not be able to become secure + */ + if (is_vm_hugetlb_page(vma)) + goto out; + + rc = 0; + /* we take an extra reference here */ + page = follow_page(vma, uaddr, FOLL_WRITE | FOLL_GET); + if (IS_ERR_OR_NULL(page)) + goto out; + rc = uv_destroy_owned_page(page_to_phys(page)); + /* + * Fault handlers can race; it is possible that two CPUs will fault + * on the same secure page. One CPU can destroy the page, reboot, + * re-enter secure mode and import it, while the second CPU was + * stuck at the beginning of the handler. At some point the second + * CPU will be able to progress, and it will not be able to destroy + * the page. In that case we do not want to terminate the process, + * we instead try to export the page. + */ + if (rc) + rc = uv_convert_owned_from_secure(page_to_phys(page)); + put_page(page); +out: + mmap_read_unlock(gmap->mm); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_destroy_page); + /* * To be called with the page locked or with an extra reference! This will * prevent gmap_make_secure from touching the page concurrently. Having 2 diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index e173b6187ad5..af1ac49168fb 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -837,6 +837,16 @@ NOKPROBE_SYMBOL(do_non_secure_storage_access); void do_secure_storage_violation(struct pt_regs *regs) { + unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK; + struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; + + /* + * If the VM has been rebooted, its address space might still contain + * secure pages from the previous boot. + * Clear the page so it can be reused. + */ + if (!gmap_destroy_page(gmap, gaddr)) + return; /* * Either KVM messed up the secure guest mapping or the same * page is mapped into multiple secure guests. |