From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"Wei Liu" <wl@xen.org>, "Jan Beulich" <JBeulich@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [Xen-devel] [PATCH v2 2/5] x86/boot: Size the boot/directmap mappings dynamically
Date: Fri, 17 Jan 2020 20:42:20 +0000 [thread overview]
Message-ID: <20200117204223.30076-3-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <20200117204223.30076-1-andrew.cooper3@citrix.com>
... rather than presuming that 16M will do. On the EFI side, use
l2e_add_flags() to reduce the code-generation overhead of using
l2e_from_paddr() twice.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wl@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
v2:
* Drop adjustment to the linker script. There are more 16M issues to find.
---
xen/arch/x86/boot/head.S | 21 +++++++++++++--------
xen/arch/x86/efi/efi-boot.h | 23 ++++++++++++++++++-----
2 files changed, 31 insertions(+), 13 deletions(-)
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index ef9f562505..0137ee99a4 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -687,14 +687,19 @@ trampoline_setup:
* handling/walking), and identity map Xen into bootmap (needed for
* the transition into long mode), using 2M superpages.
*/
- lea sym_esi(start),%ebx
- lea (1<<L2_PAGETABLE_SHIFT)*7+(PAGE_HYPERVISOR_RWX|_PAGE_PSE)(%ebx),%eax
- shr $(L2_PAGETABLE_SHIFT-3),%ebx
- mov $8,%ecx
-1: mov %eax,sym_fs(l2_bootmap)-8(%ebx,%ecx,8)
- mov %eax,sym_fs(l2_directmap)-8(%ebx,%ecx,8)
- sub $(1<<L2_PAGETABLE_SHIFT),%eax
- loop 1b
+ lea sym_esi(_start), %ecx
+ lea -1 + sym_esi(_end), %edx
+ lea _PAGE_PSE + PAGE_HYPERVISOR_RWX(%ecx), %eax /* PTE to write. */
+ shr $L2_PAGETABLE_SHIFT, %ecx /* First slot to write. */
+ shr $L2_PAGETABLE_SHIFT, %edx /* Final slot to write. */
+
+1: mov %eax, sym_offs(l2_bootmap) (%esi, %ecx, 8)
+ mov %eax, sym_offs(l2_directmap)(%esi, %ecx, 8)
+ add $1, %ecx
+ add $1 << L2_PAGETABLE_SHIFT, %eax
+
+ cmp %edx, %ecx
+ jbe 1b
/* Initialize L3 boot-map page directory entries. */
lea __PAGE_HYPERVISOR+(L2_PAGETABLE_ENTRIES*8)*3+sym_esi(l2_bootmap),%eax
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index ce07aedf45..bf7b0a61dc 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -611,15 +611,28 @@ static void __init efi_arch_memory_setup(void)
* Map Xen into the directmap (needed for early-boot pagetable
* handling/walking), and identity map Xen into bootmap (needed for the
* transition from the EFI pagetables to Xen), using 2M superpages.
+ *
+ * NB: We are currently in physical mode, so a RIP-relative relocation
+ * against _start/_end gets their real position in memory, which are the
+ * appropriate l2 slots to map.
*/
- for ( i = 0; i < 8; ++i )
+#define l2_4G_offset(a) \
+ (((UINTN)(a) >> L2_PAGETABLE_SHIFT) & (4 * L2_PAGETABLE_ENTRIES - 1))
+
+ for ( i = l2_4G_offset(_start);
+ i <= l2_4G_offset(_end - 1); ++i )
{
- unsigned int slot = (xen_phys_start >> L2_PAGETABLE_SHIFT) + i;
- paddr_t addr = slot << L2_PAGETABLE_SHIFT;
+ l2_pgentry_t pte = l2e_from_paddr(i << L2_PAGETABLE_SHIFT,
+ __PAGE_HYPERVISOR | _PAGE_PSE);
+
+ l2_bootmap[i] = pte;
+
+ /* Bootmap RWX/Non-global. Directmap RW/Global. */
+ l2e_add_flags(pte, PAGE_HYPERVISOR);
- l2_directmap[slot] = l2e_from_paddr(addr, PAGE_HYPERVISOR|_PAGE_PSE);
- l2_bootmap[slot] = l2e_from_paddr(addr, __PAGE_HYPERVISOR|_PAGE_PSE);
+ l2_directmap[i] = pte;
}
+#undef l2_4G_offset
}
static void __init efi_arch_handle_module(struct file *file, const CHAR16 *name,
--
2.11.0
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next prev parent reply other threads:[~2020-01-17 20:42 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 20:42 [Xen-devel] [PATCH v2 0/5] x86: Remove more 16M total-size restrictions Andrew Cooper
2020-01-17 20:42 ` [Xen-devel] [PATCH v2 1/5] x86/boot: Create the l2_xenmap[] mappings dynamically Andrew Cooper
2020-01-20 10:29 ` Jan Beulich
2020-01-17 20:42 ` Andrew Cooper [this message]
2020-01-20 10:30 ` [Xen-devel] [PATCH v2 2/5] x86/boot: Size the boot/directmap " Jan Beulich
2020-01-17 20:42 ` [Xen-devel] [PATCH v2 3/5] x86/boot: Drop explicit %fs uses Andrew Cooper
2020-01-20 10:35 ` Jan Beulich
2020-01-17 20:42 ` [Xen-devel] [PATCH v2 4/5] x86/boot: Simplify pagetable manipulation loops Andrew Cooper
2020-01-20 10:46 ` Jan Beulich
2020-01-22 15:43 ` Andrew Cooper
2020-01-17 20:42 ` [Xen-devel] [PATCH v2 5/5] x86/boot: Drop sym_fs() Andrew Cooper
2020-01-20 11:39 ` Jan Beulich
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