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Re: [Xen-devel] [PATCH RFC 15/18] arm: Add ability to relocate Xen in over 4GB space
Hello,
On 18/05/16 17:32, Andrii Anisov wrote:
From: Iurii Konovalenko <iurii.konovalenko@xxxxxxxxxxxxxxx>
Move Xen to the end of physical memory
Can you explain why? As Ian campbell said on the previous version sent
last year [1], Xen itself (i.e .text, .bss and .data, not the xenheap
itself) is at most 2MB. Are your constraints such that at a 4GB-2MB
(i.e. 4096M) of lowmem would not be acceptable?
Also, this patch looks very similar to the one you have sent last year
[2]. Most of the comments in this thread are still valid, so I will not
repeat them here.
Regards,
Signed-off-by: Iurii Konovalenko <iurii.konovalenko@xxxxxxxxxxxxxxx>
---
xen/Rules.mk | 1 +
xen/arch/arm/arm32/head.S | 21 ++++++++++++++++++++-
xen/arch/arm/domain_build.c | 2 +-
xen/arch/arm/platforms/omap5.c | 17 ++++++++++++++---
xen/arch/arm/platforms/rcar2.c | 9 ++++++++-
xen/arch/arm/setup.c | 21 ++++++++++
++++++++++-
xen/arch/arm/smpboot.c | 33 +++++++++++++++++++++++++++++----
7 files changed, 93 insertions(+), 11 deletions(-)
diff --git a/xen/Rules.mk b/xen/Rules.mk
index feb08d6..fbd34a5 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -64,6 +64,7 @@ CFLAGS-$(HAS_PCI) += -DHAS_PCI
CFLAGS-$(HAS_IOPORTS) += -DHAS_IOPORTS
CFLAGS-$(HAS_PDX) += -DHAS_PDX
CFLAGS-$(frame_pointer) += -fno-omit-frame-pointer -DCONFIG_FRAME_POINTER
+CFLAGS-$(ARM32_RELOCATE_OVER_4GB) += -DARM32_RELOCATE_OVER_4GB
ifneq ($(max_phys_cpus),)
CFLAGS-y += -DMAX_PHYS_CPUS=$(max_phys_cpus)
diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
index e1f29bd..a644d6d 100644
--- a/xen/arch/arm/arm32/head.S
+++ b/xen/arch/arm/arm32/head.S
@@ -262,8 +262,21 @@ cpu_init_done:
add r4, r4, r10 /* r4 := paddr (boot_pagetable) */
mov r5, #0 /* r4:r5 is paddr (boot_pagetable) */
mcrr CP64(r4, r5, HTTBR)
+#ifdef ARM32_RELOCATE_OVER_4GB
+ teq r7, #0
+ beq 1f /* construct pagetable if CPU0 */
- /* Setup boot_pgtable: */
+ /*Skip constructing TLBs for secondary CPUs, use constracted by CPU0*/
+ PRINT("- Skip construction pagetable, using CPU0 table @")
+ mov r0, r5
+ bl putn
+ mov r0, r4
+ bl putn
+ PRINT(" -\r\n")
+ bne skip_constructing
+#endif
+
+1: /* Setup boot_pgtable: */
ldr r1, =boot_second
add r1, r1, r10 /* r1 := paddr (boot_second) */
@@ -346,6 +359,7 @@ virtphys_clash:
PRINT("- Unable to build boot page tables - virt and phys addresses clash.
-\r\n")
b fail
+skip_constructing:
1:
PRINT("- Turning on paging -\r\n")
@@ -427,6 +441,11 @@ paging:
* setup in init_secondary_pagetables. */
ldr r4, =init_ttbr /* VA of HTTBR value stashed by CPU 0 */
+#ifdef ARM32_RELOCATE_OVER_4GB
+ ldr r1, =_start
+ sub r4, r1
+ add r4, #BOOT_RELOC_VIRT_START
+#endif
ldrd r4, r5, [r4] /* Actual value */
dsb
mcrr CP64(r4, r5, HTTBR)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index b48718d..f06792e 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1487,7 +1487,7 @@ static void __init find_gnttab_region(struct domain *d,
if ( (kinfo->gnttab_size >> PAGE_SHIFT) < max_grant_frames )
panic("Cannot find a space for the grant table region\n");
-#ifdef CONFIG_ARM_32
+#if defined(CONFIG_ARM_32) && !defined(ARM32_RELOCATE_OVER_4GB)
/*
* The gnttab region must be under 4GB in order to work with DOM0
* using short page table.
diff --git a/xen/arch/arm/platforms/omap5.c b/xen/arch/arm/platforms/omap5.c
index a49ba62..fe77397 100644
--- a/xen/arch/arm/platforms/omap5.c
+++ b/xen/arch/arm/platforms/omap5.c
@@ -25,6 +25,10 @@
#include <xen/vmap.h>
#include <asm/io.h>
+#ifdef ARM32_RELOCATE_OVER_4GB
+extern paddr_t xen_relocation_offset;
+#endif
+
static uint16_t num_den[8][2] = {
{ 0, 0 }, /* not used */
{ 26 * 64, 26 * 125 }, /* 12.0 Mhz */
@@ -132,9 +136,16 @@ static int __init omap5_smp_init(void)
}
printk("Set AuxCoreBoot1 to %"PRIpaddr" (%p)\n",
- __pa(init_secondary), init_secondary);
- writel(__pa(init_secondary), wugen_base + OMAP_AUX_CORE_BOOT_1_OFFSET);
-
+ __pa(init_secondary)
+#ifdef ARM32_RELOCATE_OVER_4GB
+ - xen_relocation_offset
+#endif
+ , init_secondary);
+ writel(__pa(init_secondary)
+#ifdef ARM32_RELOCATE_OVER_4GB
+ - xen_relocation_offset
+#endif
+ , wugen_base + OMAP_AUX_CORE_BOOT_1_OFFSET);
printk("Set AuxCoreBoot0 to 0x20\n");
writel(0x20, wugen_base + OMAP_AUX_CORE_BOOT_0_OFFSET);
diff --git a/xen/arch/arm/platforms/rcar2.c b/xen/arch/arm/platforms/rcar2.c
index bb25751..26973f6 100644
--- a/xen/arch/arm/platforms/rcar2.c
+++ b/xen/arch/arm/platforms/rcar2.c
@@ -25,6 +25,9 @@
#define RCAR2_RAM_SIZE 0x1000
#define RCAR2_SMP_START_OFFSET 0xFFC
+#ifdef ARM32_RELOCATE_OVER_4GB
+extern paddr_t xen_relocation_offset;
+#endif
static int __init rcar2_smp_init(void)
{
void __iomem *pram;
@@ -38,7 +41,11 @@ static int __init rcar2_smp_init(void)
}
/* setup reset vectors */
- writel(__pa(init_secondary), pram + RCAR2_SMP_START_OFFSET);
+ writel(__pa(init_secondary)
+#ifdef ARM32_RELOCATE_OVER_4GB
+ - xen_relocation_offset
+#endif
+ , pram + RCAR2_SMP_START_OFFSET);
iounmap(pram);
sev();
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 48f734f..7e507bc 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -394,9 +394,13 @@ static paddr_t __init get_xen_paddr(void)
const struct membank *bank = &mi->bank[i];
paddr_t s, e;
+ //TODO: investigate reason why we need contiguous memory
+ //and how it can affect relocation of Xen in over 4GB space
+#ifndef ARM32_RELOCATE_OVER_4GB
/* We can only deal with contiguous memory at the moment */
if ( last_end != bank->start )
break;
+#endif
last_end = bank->start + bank->size;
@@ -407,7 +411,7 @@ static paddr_t __init get_xen_paddr(void)
if ( !e )
continue;
-#ifdef CONFIG_ARM_32
+#if defined (CONFIG_ARM_32) && !defined(ARM32_RELOCATE_OVER_4GB)
/* Xen must be under 4GB */
if ( e > 0x100000000ULL )
e = 0x100000000ULL;
@@ -698,6 +702,9 @@ void __init setup_cache(void)
cacheline_bytes = 1U << (4 + (ccsid & 0x7));
}
+#ifdef ARM32_RELOCATE_OVER_4GB
+paddr_t xen_relocation_offset;
+#endif
/* C entry point for boot CPU */
void __init start_xen(unsigned long boot_phys_offset,
unsigned long fdt_paddr,
@@ -739,8 +746,20 @@ void __init start_xen(unsigned long boot_phys_offset,
(paddr_t)(uintptr_t)(_end - _start + 1), NULL);
BUG_ON(!xen_bootmodule);
+#ifdef ARM32_RELOCATE_OVER_4GB
+ //save physical address of init_secondary
+ xen_relocation_offset = __pa(init_secondary);
+#endif
xen_paddr = get_xen_paddr();
setup_pagetables(boot_phys_offset, xen_paddr);
+#ifdef ARM32_RELOCATE_OVER_4GB
+ //Now Xen is relocated
+ //Calculate offset of Xen relocation
+ //It is difference between new physical address of init_secondary an old
one
+ //This offset is needed in several places when we have to write to old Xen
location
+ //(secondary CPUs run on old-located Xen and rely on some variables from
CPU0)
+ xen_relocation_offset = __pa(init_secondary) - xen_relocation_offset;
+#endif
/* Update Xen's address now that we have relocated. */
printk("Update BOOTMOD_XEN from %"PRIpaddr"-%"PRIpaddr" =>
%"PRIpaddr"-%"PRIpaddr"\n",
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index a96cda2..731144c 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -31,6 +31,9 @@
#include <xen/console.h>
#include <asm/gic.h>
#include <asm/psci.h>
+#ifdef ARM32_RELOCATE_OVER_4GB
+#include <xen/vmap.h>
+#endif
cpumask_t cpu_online_map;
cpumask_t cpu_present_map;
@@ -353,17 +356,33 @@ int __init cpu_up_send_sgi(int cpu)
return 0;
}
+#ifdef ARM32_RELOCATE_OVER_4GB
+extern paddr_t xen_relocation_offset;
+#endif
/* Bring up a remote CPU */
int __cpu_up(unsigned int cpu)
{
int rc;
s_time_t deadline;
+#ifdef ARM32_RELOCATE_OVER_4GB
+ paddr_t p_info = __pa(&smp_up_cpu) - xen_relocation_offset;
+ unsigned long* info = ioremap_nocache(p_info, sizeof(unsigned long));
+#else
+ unsigned long* info = &smp_up_cpu;
+#endif
printk("Bringing up CPU%d\n", cpu);
rc = init_secondary_pagetables(cpu);
if ( rc < 0 )
+#ifdef ARM32_RELOCATE_OVER_4GB
+ {
+ iounmap(info);
+ return rc;
+ }
+#else
return rc;
+#endif
console_start_sync(); /* Secondary may use early_printk */
@@ -374,8 +393,8 @@ int __cpu_up(unsigned int cpu)
init_data.cpuid = cpu;
/* Open the gate for this CPU */
- smp_up_cpu = cpu_logical_map(cpu);
- clean_dcache(smp_up_cpu);
+ *info = cpu_logical_map(cpu);
+ clean_dcache(*info);
rc = arch_cpu_up(cpu);
@@ -383,6 +402,9 @@ int __cpu_up(unsigned int cpu)
if ( rc < 0 )
{
+#ifdef ARM32_RELOCATE_OVER_4GB
+ iounmap(info);
+#endif
printk("Failed to bring up CPU%d\n", cpu);
return rc;
}
@@ -406,8 +428,11 @@ int __cpu_up(unsigned int cpu)
*/
init_data.stack = NULL;
init_data.cpuid = ~0;
- smp_up_cpu = MPIDR_INVALID;
- clean_dcache(smp_up_cpu);
+ *info = MPIDR_INVALID;
+ clean_dcache(*info);
+#ifdef ARM32_RELOCATE_OVER_4GB
+ iounmap(info);
+#endif
if ( !cpu_online(cpu) )
{
[1]
http://lists.xenproject.org/archives/html/xen-devel/2015-05/msg01031.html
[2]
http://lists.xenproject.org/archives/html/xen-devel/2015-04/msg00662.html
--
Julien Grall
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