|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 4/9] xen/riscv: set up fixmap mappings
Set up fixmap mappings and the L0 page table for fixmap support.
Modify the Page Table Entries (PTEs) directly in arch_pmap_map()
instead of using set_fixmap() ( which relies on map_pages_to_xen() ).
This change is necessary because PMAP is used when the domain map
page infrastructure is not yet initialized so map_pages_to_xen()
called by set_fixmap() needs to map pages on demand, which then
calls pmap() again, resulting in a loop.
The same reasoning applies to pmap_unmap(), which also modifies
PTEs directly to avoid this issue.
Define new macros in riscv/config.h for calculating
the FIXMAP_BASE address, including BOOT_FDT_VIRT_{START, SIZE},
XEN_VIRT_SIZE, and XEN_VIRT_END.
Update the check for Xen size in riscv/lds.S to use
XEN_VIRT_SIZE instead of a hardcoded constant.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in V6:
- avoid case mixing for address in RISC-V64 layout table.
- move definition of FIXMAP_BASE to new line.
- update the commit message.
---
Changes in V5:
- move definition of FIXMAP_ADDR() to asm/fixmap.h
- add gap size equal to 2 MB ( 512 * 4K one page table entry in L1 page table )
between Xen, FDT and Fixmap.
- drop the comment for FIX_LAST.
- move +1 from FIX_LAST definition to FIXADDR_TOP to be aligned with Arm.
( probably everything below FIX_LAST will be moved to a separate header in
asm/generic.h )
- correct the "changes in V4: s/'fence r,r'/'fence rw, rw'
- use write_atomic() in set_pte().
- introduce read_pte().
---
Changes in V4:
- move definitions of XEN_VIRT_SIZE, BOOT_FDT_VIRT_{START,SIZE},
FIXMAP_{BASE,ADDR}
below XEN_VIRT_START to have definitions appear in order.
- define FIX_LAST as (FIX_MISC + 1) to have a guard slot at the end.
- s/enumerated/numbered in the comment
- update the cycle which looks for L1 page table in
setup_fixmap_mapping_function() and
the comment above him.
- drop fences inside write_pte() and put 'fence rw,rw' in setup_fixmap()
before sfence_vma().
- update the commit message
- drop printk message inside setup_fixmap().
---
Changes in V3:
- s/XEN_SIZE/XEN_VIRT_SIZE
- drop usage of XEN_VIRT_END.
- sort newly introduced defines in config.h by address
- code style fixes
- drop runtime check of that pte is valid as it was checked in L1 page table
finding cycle by BUG_ON().
- update implementation of write_pte() with FENCE rw, rw.
- add BUILD_BUG_ON() to check that amount of entries aren't bigger then
entries in page table.
- drop set_fixmap, clear_fixmap declarations as they aren't used and defined
now
- update the commit message.
- s/__ASM_FIXMAP_H/ASM_FIXMAP_H
- add SPDX-License-Identifier: GPL-2.0
---
xen/arch/riscv/include/asm/config.h | 16 ++++++++--
xen/arch/riscv/include/asm/fixmap.h | 46 +++++++++++++++++++++++++++++
xen/arch/riscv/include/asm/mm.h | 2 ++
xen/arch/riscv/include/asm/page.h | 13 ++++++++
xen/arch/riscv/mm.c | 43 +++++++++++++++++++++++++++
xen/arch/riscv/setup.c | 2 ++
xen/arch/riscv/xen.lds.S | 2 +-
7 files changed, 121 insertions(+), 3 deletions(-)
create mode 100644 xen/arch/riscv/include/asm/fixmap.h
diff --git a/xen/arch/riscv/include/asm/config.h
b/xen/arch/riscv/include/asm/config.h
index 50583aafdc..7dbb235685 100644
--- a/xen/arch/riscv/include/asm/config.h
+++ b/xen/arch/riscv/include/asm/config.h
@@ -41,8 +41,10 @@
* Start addr | End addr | Slot | area description
* ============================================================================
* ..... L2 511 Unused
- * 0xffffffffc0600000 0xffffffffc0800000 L2 511 Fixmap
- * 0xffffffffc0200000 0xffffffffc0600000 L2 511 FDT
+ * 0xffffffffc0a00000 0xffffffffc0c00000 L2 511 Fixmap
+ * ..... ( 2 MB gap )
+ * 0xffffffffc0400000 0xffffffffc0800000 L2 511 FDT
+ * ..... ( 2 MB gap )
* 0xffffffffc0000000 0xffffffffc0200000 L2 511 Xen
* ..... L2 510 Unused
* 0x3200000000 0x7f40000000 L2 200-509 Direct map
@@ -74,6 +76,16 @@
#error "unsupported RV_STAGE1_MODE"
#endif
+#define GAP_SIZE MB(2)
+
+#define XEN_VIRT_SIZE MB(2)
+
+#define BOOT_FDT_VIRT_START (XEN_VIRT_START + XEN_VIRT_SIZE + GAP_SIZE)
+#define BOOT_FDT_VIRT_SIZE MB(4)
+
+#define FIXMAP_BASE \
+ (BOOT_FDT_VIRT_START + BOOT_FDT_VIRT_SIZE + GAP_SIZE)
+
#define DIRECTMAP_SLOT_END 509
#define DIRECTMAP_SLOT_START 200
#define DIRECTMAP_VIRT_START SLOTN(DIRECTMAP_SLOT_START)
diff --git a/xen/arch/riscv/include/asm/fixmap.h
b/xen/arch/riscv/include/asm/fixmap.h
new file mode 100644
index 0000000000..63732df36c
--- /dev/null
+++ b/xen/arch/riscv/include/asm/fixmap.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * fixmap.h: compile-time virtual memory allocation
+ */
+#ifndef ASM_FIXMAP_H
+#define ASM_FIXMAP_H
+
+#include <xen/bug.h>
+#include <xen/page-size.h>
+#include <xen/pmap.h>
+
+#include <asm/page.h>
+
+#define FIXMAP_ADDR(n) (FIXMAP_BASE + (n) * PAGE_SIZE)
+
+/* Fixmap slots */
+#define FIX_PMAP_BEGIN (0) /* Start of PMAP */
+#define FIX_PMAP_END (FIX_PMAP_BEGIN + NUM_FIX_PMAP - 1) /* End of PMAP */
+#define FIX_MISC (FIX_PMAP_END + 1) /* Ephemeral mappings of hardware */
+
+#define FIX_LAST FIX_MISC
+
+#define FIXADDR_START FIXMAP_ADDR(0)
+#define FIXADDR_TOP FIXMAP_ADDR(FIX_LAST + 1)
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Direct access to xen_fixmap[] should only happen when {set,
+ * clear}_fixmap() is unusable (e.g. where we would end up to
+ * recursively call the helpers).
+ */
+extern pte_t xen_fixmap[];
+
+#define fix_to_virt(slot) ((void *)FIXMAP_ADDR(slot))
+
+static inline unsigned int virt_to_fix(vaddr_t vaddr)
+{
+ BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
+
+ return ((vaddr - FIXADDR_START) >> PAGE_SHIFT);
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* ASM_FIXMAP_H */
diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h
index 25af9e1aaa..a0bdc2bc3a 100644
--- a/xen/arch/riscv/include/asm/mm.h
+++ b/xen/arch/riscv/include/asm/mm.h
@@ -255,4 +255,6 @@ static inline unsigned int arch_get_dma_bitsize(void)
return 32; /* TODO */
}
+void setup_fixmap_mappings(void);
+
#endif /* _ASM_RISCV_MM_H */
diff --git a/xen/arch/riscv/include/asm/page.h
b/xen/arch/riscv/include/asm/page.h
index c831e16417..a7419b93b2 100644
--- a/xen/arch/riscv/include/asm/page.h
+++ b/xen/arch/riscv/include/asm/page.h
@@ -9,6 +9,7 @@
#include <xen/bug.h>
#include <xen/types.h>
+#include <asm/atomic.h>
#include <asm/mm.h>
#include <asm/page-bits.h>
@@ -81,6 +82,18 @@ static inline void flush_page_to_ram(unsigned long mfn, bool
sync_icache)
BUG_ON("unimplemented");
}
+/* Write a pagetable entry. */
+static inline void write_pte(pte_t *p, pte_t pte)
+{
+ write_atomic(p, pte);
+}
+
+/* Read a pagetable entry. */
+static inline pte_t read_pte(pte_t *p)
+{
+ return read_atomic(p);
+}
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_PAGE_H */
diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c
index 7d09e781bf..b8ff91cf4e 100644
--- a/xen/arch/riscv/mm.c
+++ b/xen/arch/riscv/mm.c
@@ -12,6 +12,7 @@
#include <asm/early_printk.h>
#include <asm/csr.h>
#include <asm/current.h>
+#include <asm/fixmap.h>
#include <asm/page.h>
#include <asm/processor.h>
@@ -49,6 +50,9 @@ stage1_pgtbl_root[PAGETABLE_ENTRIES];
pte_t __section(".bss.page_aligned") __aligned(PAGE_SIZE)
stage1_pgtbl_nonroot[PGTBL_INITIAL_COUNT * PAGETABLE_ENTRIES];
+pte_t __section(".bss.page_aligned") __aligned(PAGE_SIZE)
+xen_fixmap[PAGETABLE_ENTRIES];
+
#define HANDLE_PGTBL(curr_lvl_num) \
index = pt_index(curr_lvl_num, page_addr); \
if ( pte_is_valid(pgtbl[index]) ) \
@@ -191,6 +195,45 @@ static bool __init check_pgtbl_mode_support(struct
mmu_desc *mmu_desc,
return is_mode_supported;
}
+void __init setup_fixmap_mappings(void)
+{
+ pte_t *pte, tmp;
+ unsigned int i;
+
+ BUILD_BUG_ON(FIX_LAST >= PAGETABLE_ENTRIES);
+
+ pte = &stage1_pgtbl_root[pt_index(HYP_PT_ROOT_LEVEL, FIXMAP_ADDR(0))];
+
+ /*
+ * In RISC-V page table levels are numbered from Lx to L0 where
+ * x is the highest page table level for currect MMU mode ( for example,
+ * for Sv39 has 3 page tables so the x = 2 (L2 -> L1 -> L0) ).
+ *
+ * In this cycle we want to find L1 page table because as L0 page table
+ * xen_fixmap[] will be used.
+ */
+ for ( i = HYP_PT_ROOT_LEVEL; i-- > 1; )
+ {
+ BUG_ON(!pte_is_valid(*pte));
+
+ pte = (pte_t *)LOAD_TO_LINK(pte_to_paddr(*pte));
+ pte = &pte[pt_index(i, FIXMAP_ADDR(0))];
+ }
+
+ BUG_ON(pte_is_valid(*pte));
+
+ tmp = paddr_to_pte(LINK_TO_LOAD((unsigned long)&xen_fixmap), PTE_TABLE);
+ write_pte(pte, tmp);
+
+ RISCV_FENCE(rw, rw);
+ sfence_vma();
+
+ /*
+ * We only need the zeroeth table allocated, but not the PTEs set, because
+ * set_fixmap() will set them on the fly.
+ */
+}
+
/*
* setup_initial_pagetables:
*
diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
index 4defad68f4..13f0e8c77d 100644
--- a/xen/arch/riscv/setup.c
+++ b/xen/arch/riscv/setup.c
@@ -46,6 +46,8 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
test_macros_from_bug_h();
#endif
+ setup_fixmap_mappings();
+
printk("All set up\n");
for ( ;; )
diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
index 070b19d915..7a683f6065 100644
--- a/xen/arch/riscv/xen.lds.S
+++ b/xen/arch/riscv/xen.lds.S
@@ -181,6 +181,6 @@ ASSERT(!SIZEOF(.got.plt), ".got.plt non-empty")
* Changing the size of Xen binary can require an update of
* PGTBL_INITIAL_COUNT.
*/
-ASSERT(_end - _start <= MB(2), "Xen too large for early-boot assumptions")
+ASSERT(_end - _start <= XEN_VIRT_SIZE, "Xen too large for early-boot
assumptions")
ASSERT(_ident_end - _ident_start <= IDENT_AREA_SIZE, "identity region is too
big");
--
2.46.0
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |