[Xen-devel] [PATCH v2 08/17] xen: x86/mm: add SGX EPC management

[Boqun Feng <boqun.feng@xxxxxxxxx>]

As now the heap allocator supports EPC pages, the management of EPC
pages is simply putting EPC pages into the heap at booting up if SGX is
supported and the EPC section is reported consistently. Allocation and
reclamation are just heap allocation and reclamation with MEMF_epc.

One more thing we need to do is to populate the portion of EPC pages in
the 'frame_table' and set up the mapping properly.

SGX would be disabled, if EPC initialization found any problem.

Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
---
 xen/arch/x86/sgx.c        | 161 ++++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-x86/sgx.h |   3 +
 2 files changed, 164 insertions(+)

diff --git a/xen/arch/x86/sgx.c b/xen/arch/x86/sgx.c
index ead917543f3e..9409b041e4f7 100644
--- a/xen/arch/x86/sgx.c
+++ b/xen/arch/x86/sgx.c
@@ -22,6 +22,8 @@
 #include <asm/cpufeature.h>
 #include <asm/msr-index.h>
 #include <asm/msr.h>
+#include <xen/errno.h>
+#include <xen/mm.h>
 #include <asm/sgx.h>
 
 struct sgx_cpuinfo __read_mostly boot_sgx_cpudata;
@@ -29,6 +31,13 @@ struct sgx_cpuinfo __read_mostly boot_sgx_cpudata;
 static bool __read_mostly opt_sgx_enabled = false;
 boolean_param("sgx", opt_sgx_enabled);
 
+#define total_epc_npages (boot_sgx_cpudata.epc_size >> PAGE_SHIFT)
+#define epc_base_mfn (boot_sgx_cpudata.epc_base >> PAGE_SHIFT)
+#define epc_base_maddr (boot_sgx_cpudata.epc_base)
+#define epc_end_maddr (epc_base_maddr + boot_sgx_cpudata.epc_size)
+
+static void *epc_base_vaddr = NULL;
+
 static void __detect_sgx(struct sgx_cpuinfo *sgxinfo)
 {
     u32 eax, ebx, ecx, edx;
@@ -166,11 +175,163 @@ static void __init print_sgx_cpuinfo(struct sgx_cpuinfo 
*sgxinfo)
            boot_sgx_cpudata.epc_base + boot_sgx_cpudata.epc_size);
 }
 
+struct ft_page {
+    struct page_info *pg;
+    unsigned int order;
+    unsigned long idx;
+    struct list_head list;
+};
+
+static int extend_epc_frametable(unsigned long smfn, unsigned long emfn)
+{
+    unsigned long idx;
+    LIST_HEAD(ft_pages);
+    struct ft_page *ftp, *nftp;
+    int rc = 0;
+
+    for ( ; smfn < emfn; smfn += PDX_GROUP_COUNT )
+    {
+        idx = pfn_to_pdx(smfn) / PDX_GROUP_COUNT;
+
+        if (!test_bit(idx, pdx_group_valid))
+        {
+            unsigned long s = (unsigned long)pdx_to_page(idx * 
PDX_GROUP_COUNT);
+            struct page_info *pg;
+
+            ftp = xzalloc(struct ft_page);
+
+            if ( !ftp )
+            {
+                rc = -ENOMEM;
+                goto out;
+            }
+
+            pg = alloc_domheap_pages(NULL, PDX_GROUP_SHIFT - PAGE_SHIFT, 0);
+
+            if ( !pg )
+            {
+                xfree(ftp);
+                rc = -ENOMEM;
+                goto out;
+            }
+
+            ftp->order = PDX_GROUP_SHIFT - PAGE_SHIFT;
+            ftp->pg = pg;
+            ftp->idx = idx;
+
+            list_add_tail(&ftp->list, &ft_pages);
+
+            map_pages_to_xen(s, page_to_mfn(pg),
+                             1UL << (PDX_GROUP_SHIFT - PAGE_SHIFT),
+                             PAGE_HYPERVISOR);
+            memset((void *)s, 0, sizeof(struct page_info) * PDX_GROUP_COUNT);
+        }
+    }
+
+out:
+    list_for_each_entry_safe(ftp, nftp, &ft_pages, list)
+    {
+        if ( rc )
+        {
+            unsigned long s = (unsigned long)pdx_to_page(ftp->idx * 
PDX_GROUP_COUNT);
+
+            destroy_xen_mappings(s, s + (1UL << PDX_GROUP_SHIFT));
+            free_domheap_pages(ftp->pg, ftp->order);
+        }
+        list_del(&ftp->list);
+        xfree(ftp);
+    }
+
+    if ( !rc )
+        set_pdx_range(smfn, emfn);
+
+    return rc;
+}
+
+static int __init init_epc_frametable(unsigned long mfn, unsigned long npages)
+{
+    return extend_epc_frametable(mfn, mfn + npages);
+}
+
+static int __init init_epc_heap(void)
+{
+    struct page_info *pg;
+    unsigned long nrpages = total_epc_npages;
+    unsigned long i;
+    int rc = 0;
+
+    rc = init_epc_frametable(epc_base_mfn, nrpages);
+
+    if ( rc )
+        return rc;
+
+    for ( i = 0; i < nrpages; i++ )
+    {
+        pg = mfn_to_page(epc_base_mfn + i);
+        pg->count_info |= PGC_epc;
+    }
+
+    init_domheap_pages(epc_base_maddr, epc_end_maddr);
+
+    return rc;
+}
+
+struct page_info *alloc_epc_page(void)
+{
+    struct page_info *pg = alloc_domheap_page(NULL, MEMF_epc);
+
+    if ( !pg )
+        return NULL;
+
+    /*
+     * PGC_epc will be cleared in free_heap_pages(), so we add it back at
+     * allocation time, so that is_epc_page() will return true, when this page
+     * gets freed.
+     */
+    pg->count_info |= PGC_epc;
+
+    return pg;
+}
+
+void free_epc_page(struct page_info *epg)
+{
+    free_domheap_page(epg);
+}
+
+
+static int __init sgx_init_epc(void)
+{
+    int rc = 0;
+
+    epc_base_vaddr = ioremap_wb(epc_base_maddr,
+                                total_epc_npages << PAGE_SHIFT);
+
+    if ( !epc_base_maddr )
+    {
+        printk("Failed to ioremap_wb EPC range. Disable SGX.\n");
+
+        return -EFAULT;
+    }
+
+    rc = init_epc_heap();
+
+    if ( rc )
+    {
+        printk("Failed to init heap for EPC pages. Disable SGX.\n");
+        iounmap(epc_base_vaddr);
+    }
+
+    return rc;
+}
+
 static int __init sgx_init(void)
 {
     if ( !cpu_has_sgx )
         goto not_supported;
 
+    if ( sgx_init_epc() )
+        goto not_supported;
+
     print_sgx_cpuinfo(&boot_sgx_cpudata);
 
     return 0;
diff --git a/xen/include/asm-x86/sgx.h b/xen/include/asm-x86/sgx.h
index b37ebde64e84..8fed664fa154 100644
--- a/xen/include/asm-x86/sgx.h
+++ b/xen/include/asm-x86/sgx.h
@@ -58,4 +58,7 @@ void detect_sgx(struct sgx_cpuinfo *sgxinfo);
 void disable_sgx(void);
 #define sgx_lewr() (boot_sgx_cpudata.lewr)
 
+struct page_info *alloc_epc_page(void);
+void free_epc_page(struct page_info *epg);
+
 #endif  /* __ASM_X86_SGX_H__ */
-- 
2.15.0


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