[PATCH] x86/setup: call early_reserve_memory() earlier

From: Juergen Gross
Date: Tue Sep 14 2021 - 05:41:17 EST


Commit a799c2bd29d19c565 ("x86/setup: Consolidate early memory
reservations") introduced early_reserve_memory() to do all needed
initial memblock_reserve() calls in one function. Unfortunately the
call of early_reserve_memory() is done too late for Xen dom0, as in
some cases a Xen hook called by e820__memory_setup() will need those
memory reservations to have happened already.

Move the call of early_reserve_memory() to the beginning of
setup_arch() in order to avoid such problems.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: a799c2bd29d19c565 ("x86/setup: Consolidate early memory reservations")
Reported-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
arch/x86/kernel/setup.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 79f164141116..f369c51ec580 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -757,6 +757,18 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)

void __init setup_arch(char **cmdline_p)
{
+ /*
+ * Do some memory reservations *before* memory is added to
+ * memblock, so memblock allocations won't overwrite it.
+ * Do it after early param, so we could get (unlikely) panic from
+ * serial.
+ *
+ * After this point everything still needed from the boot loader or
+ * firmware or kernel text should be early reserved or marked not
+ * RAM in e820. All other memory is free game.
+ */
+ early_reserve_memory();
+
#ifdef CONFIG_X86_32
memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));

@@ -876,18 +888,6 @@ void __init setup_arch(char **cmdline_p)

parse_early_param();

- /*
- * Do some memory reservations *before* memory is added to
- * memblock, so memblock allocations won't overwrite it.
- * Do it after early param, so we could get (unlikely) panic from
- * serial.
- *
- * After this point everything still needed from the boot loader or
- * firmware or kernel text should be early reserved or marked not
- * RAM in e820. All other memory is free game.
- */
- early_reserve_memory();
-
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Memory used by the kernel cannot be hot-removed because Linux
--
2.26.2