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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 for-next v2 7/8] x86/mm: move check_descriptor to pv/mm.c
It's only needed there. Also make it static and delete the declaration
from mm.h.
No functional change.
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
xen/arch/x86/pv/mm.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++
xen/arch/x86/x86_64/mm.c | 87 ------------------------------------------------
xen/include/asm-x86/mm.h | 2 --
3 files changed, 86 insertions(+), 89 deletions(-)
diff --git a/xen/arch/x86/pv/mm.c b/xen/arch/x86/pv/mm.c
index 48d3fe184b..96f2431756 100644
--- a/xen/arch/x86/pv/mm.c
+++ b/xen/arch/x86/pv/mm.c
@@ -220,6 +220,92 @@ static void invalidate_shadow_ldt(struct vcpu *v, int
flush)
spin_unlock(&v->arch.pv_vcpu.shadow_ldt_lock);
}
+/* Returns TRUE if given descriptor is valid for GDT or LDT. */
+static int check_descriptor(const struct domain *dom, struct desc_struct *d)
+{
+ u32 a = d->a, b = d->b;
+ u16 cs;
+ unsigned int dpl;
+
+ /* A not-present descriptor will always fault, so is safe. */
+ if ( !(b & _SEGMENT_P) )
+ return 1;
+
+ /* Check and fix up the DPL. */
+ dpl = (b >> 13) & 3;
+ __fixup_guest_selector(dom, dpl);
+ b = (b & ~_SEGMENT_DPL) | (dpl << 13);
+
+ /* All code and data segments are okay. No base/limit checking. */
+ if ( (b & _SEGMENT_S) )
+ {
+ if ( is_pv_32bit_domain(dom) )
+ {
+ unsigned long base, limit;
+
+ if ( b & _SEGMENT_L )
+ goto bad;
+
+ /*
+ * Older PAE Linux guests use segments which are limited to
+ * 0xf6800000. Extend these to allow access to the larger read-only
+ * M2P table available in 32on64 mode.
+ */
+ base = (b & (0xff << 24)) | ((b & 0xff) << 16) | (a >> 16);
+
+ limit = (b & 0xf0000) | (a & 0xffff);
+ limit++; /* We add one because limit is inclusive. */
+
+ if ( (b & _SEGMENT_G) )
+ limit <<= 12;
+
+ if ( (base == 0) && (limit > HYPERVISOR_COMPAT_VIRT_START(dom)) )
+ {
+ a |= 0x0000ffff;
+ b |= 0x000f0000;
+ }
+ }
+
+ goto good;
+ }
+
+ /* Invalid type 0 is harmless. It is used for 2nd half of a call gate. */
+ if ( (b & _SEGMENT_TYPE) == 0x000 )
+ return 1;
+
+ /* Everything but a call gate is discarded here. */
+ if ( (b & _SEGMENT_TYPE) != 0xc00 )
+ goto bad;
+
+ /* Validate the target code selector. */
+ cs = a >> 16;
+ if ( !guest_gate_selector_okay(dom, cs) )
+ goto bad;
+ /*
+ * Force DPL to zero, causing a GP fault with its error code indicating
+ * the gate in use, allowing emulation. This is necessary because with
+ * native guests (kernel in ring 3) call gates cannot be used directly
+ * to transition from user to kernel mode (and whether a gate is used
+ * to enter the kernel can only be determined when the gate is being
+ * used), and with compat guests call gates cannot be used at all as
+ * there are only 64-bit ones.
+ * Store the original DPL in the selector's RPL field.
+ */
+ b &= ~_SEGMENT_DPL;
+ cs = (cs & ~3) | dpl;
+ a = (a & 0xffffU) | (cs << 16);
+
+ /* Reserved bits must be zero. */
+ if ( b & (is_pv_32bit_domain(dom) ? 0xe0 : 0xff) )
+ goto bad;
+
+ good:
+ d->a = a;
+ d->b = b;
+ return 1;
+ bad:
+ return 0;
+}
static int alloc_segdesc_page(struct page_info *page)
{
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index 19a14e8829..0bf85a59ed 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -1018,93 +1018,6 @@ long subarch_memory_op(unsigned long cmd,
XEN_GUEST_HANDLE_PARAM(void) arg)
return rc;
}
-/* Returns TRUE if given descriptor is valid for GDT or LDT. */
-int check_descriptor(const struct domain *dom, struct desc_struct *d)
-{
- u32 a = d->a, b = d->b;
- u16 cs;
- unsigned int dpl;
-
- /* A not-present descriptor will always fault, so is safe. */
- if ( !(b & _SEGMENT_P) )
- return 1;
-
- /* Check and fix up the DPL. */
- dpl = (b >> 13) & 3;
- __fixup_guest_selector(dom, dpl);
- b = (b & ~_SEGMENT_DPL) | (dpl << 13);
-
- /* All code and data segments are okay. No base/limit checking. */
- if ( (b & _SEGMENT_S) )
- {
- if ( is_pv_32bit_domain(dom) )
- {
- unsigned long base, limit;
-
- if ( b & _SEGMENT_L )
- goto bad;
-
- /*
- * Older PAE Linux guests use segments which are limited to
- * 0xf6800000. Extend these to allow access to the larger read-only
- * M2P table available in 32on64 mode.
- */
- base = (b & (0xff << 24)) | ((b & 0xff) << 16) | (a >> 16);
-
- limit = (b & 0xf0000) | (a & 0xffff);
- limit++; /* We add one because limit is inclusive. */
-
- if ( (b & _SEGMENT_G) )
- limit <<= 12;
-
- if ( (base == 0) && (limit > HYPERVISOR_COMPAT_VIRT_START(dom)) )
- {
- a |= 0x0000ffff;
- b |= 0x000f0000;
- }
- }
-
- goto good;
- }
-
- /* Invalid type 0 is harmless. It is used for 2nd half of a call gate. */
- if ( (b & _SEGMENT_TYPE) == 0x000 )
- return 1;
-
- /* Everything but a call gate is discarded here. */
- if ( (b & _SEGMENT_TYPE) != 0xc00 )
- goto bad;
-
- /* Validate the target code selector. */
- cs = a >> 16;
- if ( !guest_gate_selector_okay(dom, cs) )
- goto bad;
- /*
- * Force DPL to zero, causing a GP fault with its error code indicating
- * the gate in use, allowing emulation. This is necessary because with
- * native guests (kernel in ring 3) call gates cannot be used directly
- * to transition from user to kernel mode (and whether a gate is used
- * to enter the kernel can only be determined when the gate is being
- * used), and with compat guests call gates cannot be used at all as
- * there are only 64-bit ones.
- * Store the original DPL in the selector's RPL field.
- */
- b &= ~_SEGMENT_DPL;
- cs = (cs & ~3) | dpl;
- a = (a & 0xffffU) | (cs << 16);
-
- /* Reserved bits must be zero. */
- if ( b & (is_pv_32bit_domain(dom) ? 0xe0 : 0xff) )
- goto bad;
-
- good:
- d->a = a;
- d->b = b;
- return 1;
- bad:
- return 0;
-}
-
int pagefault_by_memadd(unsigned long addr, struct cpu_user_regs *regs)
{
struct domain *d = current->domain;
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 8e2bf91070..ca70f14500 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -411,8 +411,6 @@ static inline int get_page_and_type(struct page_info *page,
ASSERT(((_p)->count_info & PGC_count_mask) != 0); \
ASSERT(page_get_owner(_p) == (_d))
-int check_descriptor(const struct domain *, struct desc_struct *d);
-
extern bool_t opt_allow_superpage;
extern paddr_t mem_hotplug;
--
2.11.0
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