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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v7 14/14] xen/arm: add cache coloring support for Xen
Add the cache coloring support for Xen physical space.
Since Xen must be relocated to a new physical space, some relocation
functionalities must be brought back:
- the virtual address of the new space is taken from 0c18fb76323b
("xen/arm: Remove unused BOOT_RELOC_VIRT_START").
- relocate_xen() and get_xen_paddr() are taken from f60658c6ae47
("xen/arm: Stop relocating Xen").
setup_pagetables() must be adapted for coloring and for relocation. Runtime
page tables are used to map the colored space, but they are also linked in
boot tables so that the new space is temporarily available for relocation.
This implies that Xen protection must happen after the copy.
Finally, since the alternative framework needs to remap the Xen text and
inittext sections, this operation must be done in a coloring-aware way.
The function xen_remap_colored() is introduced for that.
Signed-off-by: Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>
Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
---
v7:
- added BUG_ON() checks to arch_llc_coloring_init() and
create_llc_coloring_mappings()
v6:
- squashed with BOOT_RELOC_VIRT_START patch
- consider_modules() moved in another patch
- removed psci and smpboot code because of new idmap work already handles that
- moved xen_remap_colored() in alternative.c since it's only used there
- removed xen_colored_temp[] in favor of xen_xenmap[] usage for mapping
- use of boot_module_find_by_kind() to remove the need of extra parameter in
setup_pagetables()
- moved get_xen_paddr() in arm/llc-coloring.c since it's only used there
v5:
- FIXME: consider_modules copy pasted since it got moved
v4:
- removed set_value_for_secondary() because it was wrongly cleaning cache
- relocate_xen() now calls switch_ttbr_id()
---
xen/arch/arm/alternative.c | 30 +++++++-
xen/arch/arm/arm64/mmu/head.S | 58 +++++++++++++-
xen/arch/arm/arm64/mmu/mm.c | 28 ++++++-
xen/arch/arm/include/asm/mmu/layout.h | 3 +
xen/arch/arm/llc-coloring.c | 63 +++++++++++++++-
xen/arch/arm/mmu/setup.c | 104 ++++++++++++++++++++++----
xen/arch/arm/setup.c | 10 ++-
xen/common/llc-coloring.c | 23 ++++++
xen/include/xen/llc-coloring.h | 14 ++++
9 files changed, 310 insertions(+), 23 deletions(-)
diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
index 016e66978b..8ca649b55e 100644
--- a/xen/arch/arm/alternative.c
+++ b/xen/arch/arm/alternative.c
@@ -9,6 +9,7 @@
#include <xen/init.h>
#include <xen/types.h>
#include <xen/kernel.h>
+#include <xen/llc-coloring.h>
#include <xen/mm.h>
#include <xen/vmap.h>
#include <xen/smp.h>
@@ -191,6 +192,27 @@ static int __apply_alternatives_multi_stop(void *xenmap)
return 0;
}
+static void __init *xen_remap_colored(mfn_t xen_mfn, paddr_t xen_size)
+{
+ unsigned int i;
+ void *xenmap;
+ mfn_t *xen_colored_mfns, mfn;
+
+ xen_colored_mfns = xmalloc_array(mfn_t, xen_size >> PAGE_SHIFT);
+ if ( !xen_colored_mfns )
+ panic("Can't allocate LLC colored MFNs\n");
+
+ for_each_xen_colored_mfn ( xen_mfn, mfn, i )
+ {
+ xen_colored_mfns[i] = mfn;
+ }
+
+ xenmap = vmap(xen_colored_mfns, xen_size >> PAGE_SHIFT);
+ xfree(xen_colored_mfns);
+
+ return xenmap;
+}
+
/*
* This function should only be called during boot and before CPU0 jump
* into the idle_loop.
@@ -209,8 +231,12 @@ void __init apply_alternatives_all(void)
* The text and inittext section are read-only. So re-map Xen to
* be able to patch the code.
*/
- xenmap = __vmap(&xen_mfn, 1U << xen_order, 1, 1, PAGE_HYPERVISOR,
- VMAP_DEFAULT);
+ if ( llc_coloring_enabled )
+ xenmap = xen_remap_colored(xen_mfn, xen_size);
+ else
+ xenmap = __vmap(&xen_mfn, 1U << xen_order, 1, 1, PAGE_HYPERVISOR,
+ VMAP_DEFAULT);
+
/* Re-mapping Xen is not expected to fail during boot. */
BUG_ON(!xenmap);
diff --git a/xen/arch/arm/arm64/mmu/head.S b/xen/arch/arm/arm64/mmu/head.S
index fa40b696dd..7ad2c00fd5 100644
--- a/xen/arch/arm/arm64/mmu/head.S
+++ b/xen/arch/arm/arm64/mmu/head.S
@@ -427,6 +427,61 @@ fail: PRINT("- Boot failed -\r\n")
b 1b
ENDPROC(fail)
+/*
+ * Copy Xen to new location and switch TTBR
+ * x0 ttbr
+ * x1 source address
+ * x2 destination address
+ * x3 length
+ *
+ * Source and destination must be word aligned, length is rounded up
+ * to a 16 byte boundary.
+ *
+ * MUST BE VERY CAREFUL when saving things to RAM over the copy
+ */
+ENTRY(relocate_xen)
+ /*
+ * Copy 16 bytes at a time using:
+ * x9: counter
+ * x10: data
+ * x11: data
+ * x12: source
+ * x13: destination
+ */
+ mov x9, x3
+ mov x12, x1
+ mov x13, x2
+
+1: ldp x10, x11, [x12], #16
+ stp x10, x11, [x13], #16
+
+ subs x9, x9, #16
+ bgt 1b
+
+ /*
+ * Flush destination from dcache using:
+ * x9: counter
+ * x10: step
+ * x11: vaddr
+ *
+ * This is to ensure data is visible to the instruction cache
+ */
+ dsb sy
+
+ mov x9, x3
+ ldr x10, =dcache_line_bytes /* x10 := step */
+ ldr x10, [x10]
+ mov x11, x2
+
+1: dc cvac, x11
+
+ add x11, x11, x10
+ subs x9, x9, x10
+ bgt 1b
+
+ /* No need for dsb/isb because they are alredy done in switch_ttbr_id
*/
+ b switch_ttbr_id
+
/*
* Switch TTBR
*
@@ -452,7 +507,8 @@ ENTRY(switch_ttbr_id)
/*
* 5) Flush I-cache
- * This should not be necessary but it is kept for safety.
+ * This should not be necessary in the general case, but it's needed
+ * for cache coloring because code is relocated in that case.
*/
ic iallu
isb
diff --git a/xen/arch/arm/arm64/mmu/mm.c b/xen/arch/arm/arm64/mmu/mm.c
index d2651c9486..07cf8040a2 100644
--- a/xen/arch/arm/arm64/mmu/mm.c
+++ b/xen/arch/arm/arm64/mmu/mm.c
@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <xen/init.h>
+#include <xen/llc-coloring.h>
#include <xen/mm.h>
#include <xen/pfn.h>
@@ -125,27 +126,46 @@ void update_identity_mapping(bool enable)
}
extern void switch_ttbr_id(uint64_t ttbr);
+extern void relocate_xen(uint64_t ttbr, void *src, void *dst, size_t len);
typedef void (switch_ttbr_fn)(uint64_t ttbr);
+typedef void (relocate_xen_fn)(uint64_t ttbr, void *src, void *dst, size_t
len);
void __init switch_ttbr(uint64_t ttbr)
{
- vaddr_t id_addr = virt_to_maddr(switch_ttbr_id);
- switch_ttbr_fn *fn = (switch_ttbr_fn *)id_addr;
+ vaddr_t vaddr, id_addr;
lpae_t pte;
+ if ( llc_coloring_enabled )
+ vaddr = (vaddr_t)relocate_xen;
+ else
+ vaddr = (vaddr_t)switch_ttbr_id;
+
+ id_addr = virt_to_maddr(vaddr);
+
/* Enable the identity mapping in the boot page tables */
update_identity_mapping(true);
/* Enable the identity mapping in the runtime page tables */
- pte = pte_of_xenaddr((vaddr_t)switch_ttbr_id);
+ pte = pte_of_xenaddr(vaddr);
pte.pt.table = 1;
pte.pt.xn = 0;
pte.pt.ro = 1;
write_pte(&xen_third_id[third_table_offset(id_addr)], pte);
/* Switch TTBR */
- fn(ttbr);
+ if ( llc_coloring_enabled )
+ {
+ relocate_xen_fn *fn = (relocate_xen_fn *)id_addr;
+
+ fn(ttbr, _start, (void *)BOOT_RELOC_VIRT_START, _end - _start);
+ }
+ else
+ {
+ switch_ttbr_fn *fn = (switch_ttbr_fn *)id_addr;
+
+ fn(ttbr);
+ }
/*
* Disable the identity mapping in the runtime page tables.
diff --git a/xen/arch/arm/include/asm/mmu/layout.h
b/xen/arch/arm/include/asm/mmu/layout.h
index a3b546465b..19c0ec63a5 100644
--- a/xen/arch/arm/include/asm/mmu/layout.h
+++ b/xen/arch/arm/include/asm/mmu/layout.h
@@ -30,6 +30,7 @@
* 10M - 12M Fixmap: special-purpose 4K mapping slots
* 12M - 16M Early boot mapping of FDT
* 16M - 18M Livepatch vmap (if compiled in)
+ * 16M - 24M Cache-colored Xen text, data, bss (temporary, if compiled in)
*
* 1G - 2G VMAP: ioremap and early_ioremap
*
@@ -74,6 +75,8 @@
#define BOOT_FDT_VIRT_START (FIXMAP_VIRT_START + FIXMAP_VIRT_SIZE)
#define BOOT_FDT_VIRT_SIZE _AT(vaddr_t, MB(4))
+#define BOOT_RELOC_VIRT_START (BOOT_FDT_VIRT_START + BOOT_FDT_VIRT_SIZE)
+
#ifdef CONFIG_LIVEPATCH
#define LIVEPATCH_VMAP_START (BOOT_FDT_VIRT_START + BOOT_FDT_VIRT_SIZE)
#define LIVEPATCH_VMAP_SIZE _AT(vaddr_t, MB(2))
diff --git a/xen/arch/arm/llc-coloring.c b/xen/arch/arm/llc-coloring.c
index b83540ff41..a072407e6c 100644
--- a/xen/arch/arm/llc-coloring.c
+++ b/xen/arch/arm/llc-coloring.c
@@ -9,6 +9,7 @@
#include <asm/processor.h>
#include <asm/sysregs.h>
+#include <asm/setup.h>
/* Return the LLC way size by probing the hardware */
unsigned int __init get_llc_way_size(void)
@@ -62,7 +63,67 @@ unsigned int __init get_llc_way_size(void)
return line_size * num_sets;
}
-void __init arch_llc_coloring_init(void) {}
+/**
+ * get_xen_paddr - get physical address to relocate Xen to
+ *
+ * Xen is relocated to as near to the top of RAM as possible and
+ * aligned to a XEN_PADDR_ALIGN boundary.
+ */
+static paddr_t __init get_xen_paddr(paddr_t xen_size)
+{
+ const struct meminfo *mi = &bootinfo.mem;
+ paddr_t min_size;
+ paddr_t paddr = 0;
+ unsigned int i;
+
+ min_size = (xen_size + (XEN_PADDR_ALIGN-1)) & ~(XEN_PADDR_ALIGN-1);
+
+ /* Find the highest bank with enough space. */
+ for ( i = 0; i < mi->nr_banks; i++ )
+ {
+ const struct membank *bank = &mi->bank[i];
+ paddr_t s, e;
+
+ if ( bank->size >= min_size )
+ {
+ e = consider_modules(bank->start, bank->start + bank->size,
+ min_size, XEN_PADDR_ALIGN, 0);
+ if ( !e )
+ continue;
+
+#ifdef CONFIG_ARM_32
+ /* Xen must be under 4GB */
+ if ( e > GB(4) )
+ e = GB(4);
+ if ( e < bank->start )
+ continue;
+#endif
+
+ s = e - min_size;
+
+ if ( s > paddr )
+ paddr = s;
+ }
+ }
+
+ if ( !paddr )
+ panic("Not enough memory to relocate Xen\n");
+
+ printk("Placing Xen at 0x%"PRIpaddr"-0x%"PRIpaddr"\n",
+ paddr, paddr + min_size);
+
+ return paddr;
+}
+
+void __init arch_llc_coloring_init(void)
+{
+ struct bootmodule *xen_bootmodule = boot_module_find_by_kind(BOOTMOD_XEN);
+
+ BUG_ON(!xen_bootmodule);
+
+ xen_bootmodule->size = xen_colored_map_size();
+ xen_bootmodule->start = get_xen_paddr(xen_bootmodule->size);
+}
/*
* Local variables:
diff --git a/xen/arch/arm/mmu/setup.c b/xen/arch/arm/mmu/setup.c
index de036c1f49..5823b7237f 100644
--- a/xen/arch/arm/mmu/setup.c
+++ b/xen/arch/arm/mmu/setup.c
@@ -18,6 +18,11 @@
/* Override macros from asm/page.h to make them work with mfn_t */
#undef mfn_to_virt
#define mfn_to_virt(mfn) __mfn_to_virt(mfn_x(mfn))
+#undef virt_to_mfn
+#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
+
+#define virt_to_reloc_virt(virt) \
+ (((vaddr_t)virt) - XEN_VIRT_START + BOOT_RELOC_VIRT_START)
/* Main runtime page tables */
@@ -72,6 +77,7 @@ static void __init __maybe_unused build_assertions(void)
/* 2MB aligned regions */
BUILD_BUG_ON(XEN_VIRT_START & ~SECOND_MASK);
BUILD_BUG_ON(FIXMAP_ADDR(0) & ~SECOND_MASK);
+ BUILD_BUG_ON(BOOT_RELOC_VIRT_START & ~SECOND_MASK);
/* 1GB aligned regions */
#ifdef CONFIG_ARM_32
BUILD_BUG_ON(XENHEAP_VIRT_START & ~FIRST_MASK);
@@ -135,7 +141,12 @@ static void __init __maybe_unused build_assertions(void)
lpae_t __init pte_of_xenaddr(vaddr_t va)
{
- paddr_t ma = va + phys_offset;
+ paddr_t ma;
+
+ if ( llc_coloring_enabled )
+ ma = virt_to_maddr(virt_to_reloc_virt(va));
+ else
+ ma = va + phys_offset;
return mfn_to_xen_entry(maddr_to_mfn(ma), MT_NORMAL);
}
@@ -313,9 +324,44 @@ paddr_t __init consider_modules(paddr_t s, paddr_t e,
return e;
}
+static void __init create_llc_coloring_mappings(void)
+{
+ lpae_t pte;
+ unsigned int i;
+ struct bootmodule *xen_bootmodule = boot_module_find_by_kind(BOOTMOD_XEN);
+ mfn_t start_mfn = maddr_to_mfn(xen_bootmodule->start), mfn;
+
+ for_each_xen_colored_mfn ( start_mfn, mfn, i )
+ {
+ pte = mfn_to_xen_entry(mfn, MT_NORMAL);
+ pte.pt.table = 1; /* level 3 mappings always have this bit set */
+ xen_xenmap[i] = pte;
+ }
+
+ for ( i = 0; i < XEN_NR_ENTRIES(2); i++ )
+ {
+ vaddr_t va = BOOT_RELOC_VIRT_START + (i << XEN_PT_LEVEL_SHIFT(2));
+
+ pte = mfn_to_xen_entry(virt_to_mfn(xen_xenmap +
+ i * XEN_PT_LPAE_ENTRIES),
+ MT_NORMAL);
+ pte.pt.table = 1;
+ write_pte(&boot_second[second_table_offset(va)], pte);
+ }
+}
+
/*
- * Boot-time pagetable setup.
+ * Boot-time pagetable setup with coloring support
* Changes here may need matching changes in head.S
+ *
+ * The cache coloring support consists of:
+ * - Create colored mapping that conforms to Xen color selection in
xen_xenmap[]
+ * - Link the mapping in boot page tables using BOOT_RELOC_VIRT_START as vaddr
+ * - pte_of_xenaddr() takes care of translating addresses to the new space
+ * during runtime page tables creation
+ * - Relocate xen and update TTBR with the new address in the colored space
+ * (see switch_ttbr())
+ * - Protect the new space
*/
void __init setup_pagetables(unsigned long boot_phys_offset)
{
@@ -325,6 +371,9 @@ void __init setup_pagetables(unsigned long boot_phys_offset)
phys_offset = boot_phys_offset;
+ if ( llc_coloring_enabled )
+ create_llc_coloring_mappings();
+
arch_setup_page_tables();
#ifdef CONFIG_ARM_64
@@ -352,13 +401,7 @@ void __init setup_pagetables(unsigned long
boot_phys_offset)
break;
pte = pte_of_xenaddr(va);
pte.pt.table = 1; /* third level mappings always have this bit set */
- if ( is_kernel_text(va) || is_kernel_inittext(va) )
- {
- pte.pt.xn = 0;
- pte.pt.ro = 1;
- }
- if ( is_kernel_rodata(va) )
- pte.pt.ro = 1;
+ pte.pt.xn = 0; /* Permissions will be enforced later. Allow execution
*/
xen_xenmap[i] = pte;
}
@@ -384,13 +427,48 @@ void __init setup_pagetables(unsigned long
boot_phys_offset)
ttbr = (uintptr_t) cpu0_pgtable + phys_offset;
#endif
- switch_ttbr(ttbr);
-
- xen_pt_enforce_wnx();
-
#ifdef CONFIG_ARM_32
per_cpu(xen_pgtable, 0) = cpu0_pgtable;
#endif
+
+ if ( llc_coloring_enabled )
+ ttbr = virt_to_maddr(virt_to_reloc_virt(THIS_CPU_PGTABLE));
+
+ switch_ttbr(ttbr);
+
+ /* Protect Xen */
+ for ( i = 0; i < XEN_NR_ENTRIES(3); i++ )
+ {
+ vaddr_t va = XEN_VIRT_START + (i << PAGE_SHIFT);
+ lpae_t *entry = xen_xenmap + i;
+
+ if ( !is_kernel(va) )
+ break;
+
+ pte = read_atomic(entry);
+
+ if ( is_kernel_text(va) || is_kernel_inittext(va) )
+ {
+ pte.pt.xn = 0;
+ pte.pt.ro = 1;
+ } else if ( is_kernel_rodata(va) ) {
+ pte.pt.ro = 1;
+ pte.pt.xn = 1;
+ } else {
+ pte.pt.xn = 1;
+ pte.pt.ro = 0;
+ }
+
+ write_pte(entry, pte);
+ }
+
+ /*
+ * We modified live page-tables. Ensure the TLBs are invalidated
+ * before setting enforcing the WnX permissions.
+ */
+ flush_xen_tlb_local();
+
+ xen_pt_enforce_wnx();
}
void *__init arch_vmap_virt_end(void)
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index c72c90302e..9acec8e8b1 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -724,8 +724,6 @@ void asmlinkage __init start_xen(unsigned long
boot_phys_offset,
/* Initialize traps early allow us to get backtrace when an error occurred
*/
init_traps();
- setup_pagetables(boot_phys_offset);
-
smp_clear_cpu_maps();
device_tree_flattened = early_fdt_map(fdt_paddr);
@@ -749,6 +747,14 @@ void asmlinkage __init start_xen(unsigned long
boot_phys_offset,
llc_coloring_init();
+ /*
+ * Page tables must be setup after LLC coloring initialization because
+ * coloring info are required in order to create colored mappings
+ */
+ setup_pagetables(boot_phys_offset);
+ /* Device-tree was mapped in boot page tables, remap it in the new tables
*/
+ device_tree_flattened = early_fdt_map(fdt_paddr);
+
setup_mm();
vm_init();
diff --git a/xen/common/llc-coloring.c b/xen/common/llc-coloring.c
index f1a7561d79..246b0ca04d 100644
--- a/xen/common/llc-coloring.c
+++ b/xen/common/llc-coloring.c
@@ -29,6 +29,8 @@ static unsigned int __ro_after_init xen_num_colors;
#define mfn_color_mask (max_nr_colors - 1)
#define mfn_to_color(mfn) (mfn_x(mfn) & mfn_color_mask)
+#define get_mfn_with_color(mfn, color) \
+ (_mfn((mfn_x(mfn) & ~mfn_color_mask) | (color)))
/*
* Parse the coloring configuration given in the buf string, following the
@@ -326,6 +328,27 @@ unsigned int get_max_nr_llc_colors(void)
return max_nr_colors;
}
+paddr_t __init xen_colored_map_size(void)
+{
+ return ROUNDUP((_end - _start) * max_nr_colors, XEN_PADDR_ALIGN);
+}
+
+mfn_t __init xen_colored_mfn(mfn_t mfn)
+{
+ unsigned int i, color = mfn_to_color(mfn);
+
+ for ( i = 0; i < xen_num_colors; i++ )
+ {
+ if ( color == xen_colors[i] )
+ return mfn;
+ else if ( color < xen_colors[i] )
+ return get_mfn_with_color(mfn, xen_colors[i]);
+ }
+
+ /* Jump to next color space (max_nr_colors mfns) and use the first color */
+ return get_mfn_with_color(mfn_add(mfn, max_nr_colors), xen_colors[0]);
+}
+
/*
* Local variables:
* mode: C
diff --git a/xen/include/xen/llc-coloring.h b/xen/include/xen/llc-coloring.h
index 7f8218bfb2..618833c5dc 100644
--- a/xen/include/xen/llc-coloring.h
+++ b/xen/include/xen/llc-coloring.h
@@ -26,6 +26,17 @@ static inline void domain_dump_llc_colors(const struct
domain *d) {}
static inline void domain_llc_coloring_free(struct domain *d) {}
#endif
+/**
+ * Iterate over each Xen mfn in the colored space.
+ * @start_mfn: the first mfn that needs to be colored.
+ * @mfn: the current mfn.
+ * @i: loop index.
+ */
+#define for_each_xen_colored_mfn(start_mfn, mfn, i) \
+ for ( i = 0, mfn = xen_colored_mfn(start_mfn); \
+ i < (_end - _start) >> PAGE_SHIFT; \
+ i++, mfn = xen_colored_mfn(mfn_add(mfn, 1)) )
+
unsigned int get_llc_way_size(void);
void arch_llc_coloring_init(void);
int dom0_set_llc_colors(struct domain *d);
@@ -37,6 +48,9 @@ struct page_info;
unsigned int page_to_llc_color(const struct page_info *pg);
unsigned int get_max_nr_llc_colors(void);
+paddr_t xen_colored_map_size(void);
+mfn_t xen_colored_mfn(mfn_t mfn);
+
#endif /* __COLORING_H__ */
/*
--
2.34.1
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