| Message ID | 20211001164724.220532-4-tony.luck@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Basic recovery for machine checks inside SGX | expand |
On Fri, 2021-10-01 at 09:47 -0700, Tony Luck wrote: > A memory controller patrol scrubber can report poison in a page > that isn't currently being used. > > Add "poison" field in the sgx_epc_page that can be set for an > sgx_epc_page. Check for it: > 1) When sanitizing dirty pages > 2) When freeing epc pages > > Poison is a new field separated from flags to avoid having to make > all updates to flags atomic, or integrate poison state changes into > some other locking scheme to protect flags. > > In both cases place the poisoned page on a list of poisoned epc pages > to make sure it will not be reallocated. > > Signed-off-by: Tony Luck <tony.luck@intel.com> > --- > arch/x86/kernel/cpu/sgx/main.c | 14 +++++++++++++- > arch/x86/kernel/cpu/sgx/sgx.h | 3 ++- > 2 files changed, 15 insertions(+), 2 deletions(-) Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> /Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 09fa42690ff2..653bace26100 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -43,6 +43,7 @@ static nodemask_t sgx_numa_mask; static struct sgx_numa_node *sgx_numa_nodes; static LIST_HEAD(sgx_dirty_page_list); +static LIST_HEAD(sgx_poison_page_list); /* * Reset post-kexec EPC pages to the uninitialized state. The pages are removed @@ -62,6 +63,12 @@ static void __sgx_sanitize_pages(struct list_head *dirty_page_list) page = list_first_entry(dirty_page_list, struct sgx_epc_page, list); + if (page->poison) { + list_del(&page->list); + list_add(&page->list, &sgx_poison_page_list); + continue; + } + ret = __eremove(sgx_get_epc_virt_addr(page)); if (!ret) { /* @@ -626,7 +633,11 @@ void sgx_free_epc_page(struct sgx_epc_page *page) spin_lock(&node->lock); - list_add_tail(&page->list, &node->free_page_list); + page->owner = NULL; + if (page->poison) + list_add(&page->list, &sgx_poison_page_list); + else + list_add_tail(&page->list, &node->free_page_list); sgx_nr_free_pages++; page->flags = 0; @@ -658,6 +669,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, section->pages[i].section = index; section->pages[i].flags = SGX_EPC_PAGE_IN_USE; section->pages[i].owner = NULL; + section->pages[i].poison = 0; list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list); } diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index f9202d3d6278..a990a4c9a00f 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -31,7 +31,8 @@ struct sgx_epc_page { unsigned int section; - unsigned int flags; + u16 flags; + u16 poison; struct sgx_encl_page *owner; struct list_head list; };
A memory controller patrol scrubber can report poison in a page that isn't currently being used. Add "poison" field in the sgx_epc_page that can be set for an sgx_epc_page. Check for it: 1) When sanitizing dirty pages 2) When freeing epc pages Poison is a new field separated from flags to avoid having to make all updates to flags atomic, or integrate poison state changes into some other locking scheme to protect flags. In both cases place the poisoned page on a list of poisoned epc pages to make sure it will not be reallocated. Signed-off-by: Tony Luck <tony.luck@intel.com> --- arch/x86/kernel/cpu/sgx/main.c | 14 +++++++++++++- arch/x86/kernel/cpu/sgx/sgx.h | 3 ++- 2 files changed, 15 insertions(+), 2 deletions(-)