Setup for 32bit PV userspace execution

* Implement hypercall_update_va_mapping().
* Walk the live pagetables setting _PAGE_USER.

For now, 32bit PV XTF guests need to be run on a hypervisor booted with
"smep=0 smap=0" to prevent Xen's %cr4 settings from interfering.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/arch/x86/pv/traps.c b/arch/x86/pv/traps.c
index 54e9a9b3f8627bcb1efe37493bac5ab3d791c2cc..208adcf3f08030e5fe0eacfc9bfc7615cb72913e 100644 (file)
--- a/arch/x86/pv/traps.c
+++ b/arch/x86/pv/traps.c
@@ -4,6 +4,7 @@
 
 #include <arch/x86/processor.h>
 #include <arch/x86/segment.h>
+#include <arch/x86/mm.h>
 
 /* Real entry points */
 void entry_DE(void);
@@ -85,6 +86,66 @@ void arch_init_traps(void)
     if ( rc )
         panic("Failed to set user %%cr3: %d\n", rc);
 
+#elif defined(__i386__)
+    /*
+     * Walk the live pagetables and set _PAGE_USER
+     *
+     * XTF uses a shared user/kernel address space, and _PAGE_USER must be set
+     * to permit cpl3 access to the virtual addresses without taking a
+     * pagefault.
+     *
+     * !!! WARNING !!!
+     *
+     * Because PV guests and Xen share CR4, Xen's setting of CR4.{SMEP,SMAP}
+     * interfere with 32bit PV guests.  For now, 32bit PV XTF tests require
+     * the hypervisor to be booted with "smep=0 smap=0".
+     *
+     * TODO - figure out how to work around this restriction while maintaining
+     * a shared user/kernel address space for the framework.
+     *
+     * !!! WARNING !!!
+     */
+    uint64_t *l3 = _p(start_info->pt_base);
+    unsigned long va = 0;
+
+    while ( va < __HYPERVISOR_VIRT_START_PAE )
+    {
+        unsigned int i3 = l3_table_offset(va);
+
+        if ( !(l3[i3] & _PAGE_PRESENT) )
+        {
+            va += 1UL << L3_PT_SHIFT;
+            continue;
+        }
+
+        uint64_t *l2 = maddr_to_virt(pte_to_paddr(l3[i3]));
+        unsigned int i2 = l2_table_offset(va);
+
+        if ( !(l2[i2] & _PAGE_PRESENT) )
+        {
+            va += 1UL << L2_PT_SHIFT;
+            continue;
+        }
+
+        uint64_t *l1 = maddr_to_virt(pte_to_paddr(l2[i2]));
+        unsigned int i1 = l1_table_offset(va);
+
+        if ( !(l1[i1] & _PAGE_PRESENT) )
+        {
+            va += 1UL << L1_PT_SHIFT;
+            continue;
+        }
+
+        if ( !(l1[i1] & _PAGE_USER) )
+        {
+            rc = hypercall_update_va_mapping(_p(va), l1[i1] | _PAGE_USER, 2);
+            if ( rc )
+                panic("update_va_mapping(%p, 0x%016"PRIx64") failed: %d\n",
+                      _p(va), l1[i1] | _PAGE_USER, rc);
+        }
+
+        va += 1UL << L1_PT_SHIFT;
+    }
 #endif
 }
 

diff --git a/include/arch/x86/mm.h b/include/arch/x86/mm.h
index 0706728784c15f74bbacd9ea5bb9ca0614da1194..900468ff132804c1f52958303b3984e868824afa 100644 (file)
--- a/include/arch/x86/mm.h
+++ b/include/arch/x86/mm.h
@@ -33,6 +33,11 @@ static inline void *mfn_to_virt(unsigned long mfn)
     return pfn_to_virt(m2p[mfn]);
 }
 
+static inline void *maddr_to_virt(uint64_t maddr)
+{
+    return mfn_to_virt(maddr >> PAGE_SHIFT) + (maddr & ~PAGE_MASK);
+}
+
 #undef m2p
 
 #endif /* CONFIG_ENV_pv */

diff --git a/include/arch/x86/page.h b/include/arch/x86/page.h
index adb8016ff7aa99d9d00beac21c23c44f41cf3d81..1bda7d0b044886a1c35d39b07cab22ea9f6ed9a8 100644 (file)
--- a/include/arch/x86/page.h
+++ b/include/arch/x86/page.h
@@ -22,11 +22,35 @@
 #define _PAGE_USER              0x004
 #define _PAGE_PSE               0x080
 
+#define L1_PT_SHIFT             12
+#define L2_PT_SHIFT             21
+#define L3_PT_SHIFT             30
+#define L4_PT_SHIFT             39
+
 #define L1_PT_ENTRIES           512
 #define L2_PT_ENTRIES           512
 #define L3_PT_ENTRIES           512
 #define L4_PT_ENTRIES           512
 
+#ifndef __ASSEMBLY__
+
+static inline unsigned int l1_table_offset(unsigned long va)
+{ return (va >> L1_PT_SHIFT) & (L1_PT_ENTRIES - 1); }
+static inline unsigned int l2_table_offset(unsigned long va)
+{ return (va >> L2_PT_SHIFT) & (L2_PT_ENTRIES - 1); }
+static inline unsigned int l3_table_offset(unsigned long va)
+{ return (va >> L3_PT_SHIFT) & (L3_PT_ENTRIES - 1); }
+#ifdef __x86_64__
+static inline unsigned int l4_table_offset(unsigned long va)
+{ return (va >> L4_PT_SHIFT) & (L4_PT_ENTRIES - 1); }
+#endif /* __x86_64__ */
+
+
+static inline uint64_t pte_to_paddr(uint64_t pte)
+{ return pte & 0x000ffffffffff000ULL; }
+
+#endif /* !__ASSEMBLY__ */
+
 #endif /* XTF_X86_PAGE_H */
 
 /*

diff --git a/include/arch/x86/traps.h b/include/arch/x86/traps.h
index d6c0d0c32fa84cd2e73c2d424cc3a573ac53ed6b..f2d0450a14b3ece7302b0d6d0e76b066bb30c685 100644 (file)
--- a/include/arch/x86/traps.h
+++ b/include/arch/x86/traps.h
@@ -18,6 +18,12 @@ void __noreturn arch_crash_hard(void);
 
 extern uint8_t boot_stack[2 * PAGE_SIZE];
 
+#if defined(CONFIG_ENV_pv)
+#include <xen/xen.h>
+
+extern struct start_info *start_info;
+#endif
+
 #endif /* XTF_X86_TRAPS_H */
 
 /*

diff --git a/include/xen/arch-x86/xen-x86_32.h b/include/xen/arch-x86/xen-x86_32.h
index 57a559d52a97a4566c75a821b90cabe17abceec4..efe41341294ad4c3dfc03d33d50efeb8c037f08c 100644 (file)
--- a/include/xen/arch-x86/xen-x86_32.h
+++ b/include/xen/arch-x86/xen-x86_32.h
@@ -15,6 +15,8 @@
 
 #define MACH2PHYS_VIRT_START 0xF5800000UL
 
+#define __HYPERVISOR_VIRT_START_PAE 0xF5800000UL
+
 #endif /* XEN_PUBLIC_ARCH_X86_XEN_X86_32_H */
 
 /*

diff --git a/include/xtf/hypercall.h b/include/xtf/hypercall.h
index 5102912b6cba62c27e967224044ac15f2128fac0..8a43f87520467e27bdeccdf7ef1e01f22c1aaf17 100644 (file)
--- a/include/xtf/hypercall.h
+++ b/include/xtf/hypercall.h
@@ -46,6 +46,17 @@ static inline long hypercall_stack_switch(const unsigned int ss, const void *sp)
     return HYPERCALL2(long, __HYPERVISOR_stack_switch, ss, sp);
 }
 
+static inline long hypercall_update_va_mapping(void *va, uint64_t npte,
+                                               unsigned int flags)
+{
+#ifdef __x86_64__
+    return HYPERCALL3(long, __HYPERVISOR_update_va_mapping, va, npte, flags);
+#else
+    return HYPERCALL4(long, __HYPERVISOR_update_va_mapping,
+                      va, npte, npte >> 32, flags);
+#endif
+}
+
 static inline long hypercall_mmuext_op(const mmuext_op_t ops[],
                                        unsigned int count,
                                        unsigned int *done,

diff --git a/include/xtf/types.h b/include/xtf/types.h
index 1f4b5f4003bc014949561177407540fe7a57807d..4e4b153b8e3ad4ab36ceb4e90da6d024de643f26 100644 (file)
--- a/include/xtf/types.h
+++ b/include/xtf/types.h
@@ -5,6 +5,7 @@
 #include <stdbool.h>
 #include <stdarg.h>
 #include <stddef.h>
+#include <inttypes.h>
 
 #endif /* XTF_TYPES_H */