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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen/arm: add cache coloring support for Xen image
commit e7a80636f16eb63299a6ffd6d41958e81c163991
Author: Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>
AuthorDate: Tue Dec 17 18:06:37 2024 +0100
Commit: Michal Orzel <michal.orzel@xxxxxxx>
CommitDate: Thu Dec 19 19:24:31 2024 +0100
xen/arm: add cache coloring support for Xen image
Xen image is relocated to a new colored 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>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> # common
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
---
xen/arch/arm/alternative.c | 26 ++++++++-
xen/arch/arm/arm64/mmu/head.S | 58 +++++++++++++++++-
xen/arch/arm/arm64/mmu/mm.c | 34 +++++++++++
xen/arch/arm/include/asm/mmu/layout.h | 3 +
xen/arch/arm/include/asm/mmu/mm.h | 1 +
xen/arch/arm/llc-coloring.c | 63 ++++++++++++++++++++
xen/arch/arm/mmu/setup.c | 107 +++++++++++++++++++++++++++++-----
xen/arch/arm/setup.c | 10 +++-
xen/common/llc-coloring.c | 18 ++++++
xen/include/xen/llc-coloring.h | 13 +++++
10 files changed, 313 insertions(+), 20 deletions(-)
diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
index fec7dbd2cd..2c1af6e7e4 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 +192,25 @@ 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.
@@ -209,7 +229,11 @@ 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_contig(xen_mfn, 1U << xen_order);
+ if ( llc_coloring_enabled )
+ xenmap = xen_remap_colored(xen_mfn, xen_size);
+ else
+ xenmap = vmap_contig(xen_mfn, 1U << xen_order);
+
/* 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 665a51a337..634156f83d 100644
--- a/xen/arch/arm/arm64/mmu/head.S
+++ b/xen/arch/arm/arm64/mmu/head.S
@@ -428,6 +428,61 @@ FUNC_LOCAL(fail)
b 1b
END(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
+ */
+FUNC(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 cvau, 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
*
@@ -453,7 +508,8 @@ FUNC(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 671eaadbc1..26361c4fe4 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-only */
#include <xen/init.h>
+#include <xen/llc-coloring.h>
#include <xen/mm.h>
#include <xen/pfn.h>
@@ -138,8 +139,41 @@ void update_boot_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);
+
+#ifdef CONFIG_LLC_COLORING
+void __init relocate_and_switch_ttbr(uint64_t ttbr)
+{
+ vaddr_t id_addr = virt_to_maddr(relocate_xen);
+ relocate_xen_fn *fn = (relocate_xen_fn *)id_addr;
+ lpae_t pte;
+
+ /* 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)relocate_xen);
+ pte.pt.table = 1;
+ pte.pt.xn = 0;
+ pte.pt.ro = 1;
+ write_pte(&xen_third_id[third_table_offset(id_addr)], pte);
+
+ /* Relocate Xen and switch TTBR */
+ fn(ttbr, _start, (void *)BOOT_RELOC_VIRT_START, _end - _start);
+
+ /*
+ * Disable the identity mapping in the runtime page tables.
+ * Note it is not necessary to disable it in the boot page tables
+ * because they are not going to be used by this CPU anymore.
+ */
+ update_identity_mapping(false);
+}
+#else
+void __init relocate_and_switch_ttbr(uint64_t ttbr) {}
+#endif
void __init switch_ttbr(uint64_t ttbr)
{
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/include/asm/mmu/mm.h
b/xen/arch/arm/include/asm/mmu/mm.h
index c5e03a66bf..f5a00558c4 100644
--- a/xen/arch/arm/include/asm/mmu/mm.h
+++ b/xen/arch/arm/include/asm/mmu/mm.h
@@ -31,6 +31,7 @@ void dump_pt_walk(paddr_t ttbr, paddr_t addr,
/* Switch to a new root page-tables */
extern void switch_ttbr(uint64_t ttbr);
+extern void relocate_and_switch_ttbr(uint64_t ttbr);
#endif /* __ARM_MMU_MM_H__ */
diff --git a/xen/arch/arm/llc-coloring.c b/xen/arch/arm/llc-coloring.c
index 1c7b92bc45..99ac10b610 100644
--- a/xen/arch/arm/llc-coloring.c
+++ b/xen/arch/arm/llc-coloring.c
@@ -9,6 +9,7 @@
#include <xen/llc-coloring.h>
#include <asm/processor.h>
+#include <asm/setup.h>
#include <asm/sysregs.h>
#include <asm/system.h>
@@ -64,8 +65,70 @@ unsigned int __init get_llc_way_size(void)
return line_size * num_sets;
}
+/*
+ * 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 membanks *mem = bootinfo_get_mem();
+ paddr_t min_size, paddr = 0;
+ unsigned int i;
+
+ min_size = ROUNDUP(xen_size, XEN_PADDR_ALIGN);
+
+ /* Find the highest bank with enough space. */
+ for ( i = 0; i < mem->nr_banks; i++ )
+ {
+ const struct membank *bank = &mem->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;
+}
+
+static paddr_t __init xen_colored_map_size(void)
+{
+ return ROUNDUP((_end - _start) * get_max_nr_llc_colors(), XEN_PADDR_ALIGN);
+}
+
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);
}
/*
diff --git a/xen/arch/arm/mmu/setup.c b/xen/arch/arm/mmu/setup.c
index 041e3fc1b6..30afe97781 100644
--- a/xen/arch/arm/mmu/setup.c
+++ b/xen/arch/arm/mmu/setup.c
@@ -7,6 +7,7 @@
#include <xen/init.h>
#include <xen/libfdt/libfdt.h>
+#include <xen/llc-coloring.h>
#include <xen/sections.h>
#include <xen/sizes.h>
#include <xen/vmap.h>
@@ -20,6 +21,9 @@
#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 */
/*
@@ -69,6 +73,7 @@ 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);
@@ -138,6 +143,9 @@ static void __init __maybe_unused build_assertions(void)
lpae_t __init pte_of_xenaddr(vaddr_t va)
{
+ if ( llc_coloring_enabled )
+ va = virt_to_reloc_virt(va);
+
return mfn_to_xen_entry(virt_to_mfn(va), MT_NORMAL);
}
@@ -316,6 +324,32 @@ 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.
* Changes here may need matching changes in head.S
@@ -326,6 +360,14 @@ void __init setup_pagetables(void)
lpae_t pte, *p;
int i;
+ /*
+ * In case of cache coloring, map the new physical space in the boot page
+ * tables. From now on, pte_of_xenaddr() will translate addresses to this
+ * new space.
+ */
+ if ( llc_coloring_enabled )
+ create_llc_coloring_mappings();
+
arch_setup_page_tables();
#ifdef CONFIG_ARM_64
@@ -353,13 +395,7 @@ void __init setup_pagetables(void)
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;
}
@@ -379,19 +415,58 @@ void __init setup_pagetables(void)
pte.pt.table = 1;
xen_second[second_table_offset(FIXMAP_ADDR(0))] = pte;
-#ifdef CONFIG_ARM_64
- ttbr = virt_to_maddr(xen_pgtable);
-#else
- ttbr = virt_to_maddr(cpu0_pgtable);
+#ifdef CONFIG_ARM_32
+ per_cpu(xen_pgtable, 0) = cpu0_pgtable;
#endif
- switch_ttbr(ttbr);
+ if ( llc_coloring_enabled )
+ {
+ ttbr = virt_to_maddr(virt_to_reloc_virt(THIS_CPU_PGTABLE));
+ relocate_and_switch_ttbr(ttbr);
+ }
+ else
+ {
+ ttbr = virt_to_maddr(THIS_CPU_PGTABLE);
+ switch_ttbr(ttbr);
+ }
- xen_pt_enforce_wnx();
+ /* 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;
-#ifdef CONFIG_ARM_32
- per_cpu(xen_pgtable, 0) = cpu0_pgtable;
-#endif
+ 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 5f1993ffed..68c1f30920 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -312,8 +312,6 @@ void asmlinkage __init start_xen(unsigned long fdt_paddr)
/* Initialize traps early allow us to get backtrace when an error occurred
*/
init_traps();
- setup_pagetables();
-
smp_clear_cpu_maps();
device_tree_flattened = early_fdt_map(fdt_paddr);
@@ -337,6 +335,14 @@ void asmlinkage __init start_xen(unsigned long fdt_paddr)
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();
+ /* 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 0cfaa77a2b..a572f77a09 100644
--- a/xen/common/llc-coloring.c
+++ b/xen/common/llc-coloring.c
@@ -42,6 +42,8 @@ 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
@@ -364,6 +366,22 @@ unsigned int get_max_nr_llc_colors(void)
return max_nr_colors;
}
+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;
+ 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 1216d1fbd4..45f250f9f3 100644
--- a/xen/include/xen/llc-coloring.h
+++ b/xen/include/xen/llc-coloring.h
@@ -8,6 +8,7 @@
#ifndef __XEN_LLC_COLORING_H__
#define __XEN_LLC_COLORING_H__
+#include <xen/mm-frame.h>
#include <xen/types.h>
struct domain;
@@ -30,6 +31,17 @@ 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);
@@ -38,6 +50,7 @@ int domain_set_llc_colors(struct domain *d,
int domain_set_llc_colors_from_str(struct domain *d, const char *str);
unsigned int page_to_llc_color(const struct page_info *pg);
unsigned int get_max_nr_llc_colors(void);
+mfn_t xen_colored_mfn(mfn_t mfn);
#endif /* __XEN_LLC_COLORING_H__ */
--
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