Commit 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in
init_hypervisor_platform()") moved the mapping of the shared info area
before pagetable_init(). This breaks booting as 32-bit PV guest as the
use of set_fixmap isn't possible at this time on 32-bit.
This can be worked around by populating the needed PMD on 32-bit
kernel earlier.
In order not to reimplement populate_extra_pte() using extend_brk()
for allocating new page tables extend alloc_low_pages() to do that in
case the early page table pool is not yet available.
Fixes: 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in init_hypervisor_platform()")
Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
---
Resending with corrected Fixes: tag
Boris, please take this via the Xen tree (Thomas asked us to do so)
---
arch/x86/mm/init.c | 17 ++++++++++++-----
arch/x86/xen/enlighten_pv.c | 2 ++
arch/x86/xen/mmu_pv.c | 2 ++
3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index acfab322fbe0..5c32a7665492 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -99,15 +99,22 @@ __ref void *alloc_low_pages(unsigned int num)
}
if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
- unsigned long ret;
- if (min_pfn_mapped >= max_pfn_mapped)
- panic("alloc_low_pages: ran out of memory");
- ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT,
+ unsigned long ret = 0;
+
+ if (min_pfn_mapped < max_pfn_mapped) {
+ ret = memblock_find_in_range(
+ min_pfn_mapped << PAGE_SHIFT,
max_pfn_mapped << PAGE_SHIFT,
PAGE_SIZE * num , PAGE_SIZE);
+ }
+ if (ret)
+ memblock_reserve(ret, PAGE_SIZE * num);
+ else if (can_use_brk_pgt)
+ ret = __pa(extend_brk(PAGE_SIZE * num, PAGE_SIZE));
+
if (!ret)
panic("alloc_low_pages: can not alloc memory");
- memblock_reserve(ret, PAGE_SIZE * num);
+
pfn = ret >> PAGE_SHIFT;
} else {
pfn = pgt_buf_end;
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index ee3b00c7acda..d7b2022ee301 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -122,6 +122,8 @@ static void __init xen_banner(void)
static void __init xen_pv_init_platform(void)
{
+ populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
+
set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
HYPERVISOR_shared_info = (void *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 52206ad81e4b..9e7012858420 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2171,6 +2171,8 @@ void __init xen_relocate_p2m(void)
#else /* !CONFIG_X86_64 */
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
+RESERVE_BRK(fixup_kernel_pmd, PAGE_SIZE);
+RESERVE_BRK(fixup_kernel_pte, PAGE_SIZE);
static void __init xen_write_cr3_init(unsigned long cr3)
{
--
2.13.7
On 08/20/2018 11:24 AM, Juergen Gross wrote:
> Commit 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in
> init_hypervisor_platform()") moved the mapping of the shared info area
> before pagetable_init(). This breaks booting as 32-bit PV guest as the
> use of set_fixmap isn't possible at this time on 32-bit.
>
> This can be worked around by populating the needed PMD on 32-bit
> kernel earlier.
>
> In order not to reimplement populate_extra_pte() using extend_brk()
> for allocating new page tables extend alloc_low_pages() to do that in
> case the early page table pool is not yet available.
>
> Fixes: 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in init_hypervisor_platform()")
> Signed-off-by: Juergen Gross <[email protected]>
> Reviewed-by: Thomas Gleixner <[email protected]>
> ---
> Resending with corrected Fixes: tag
> Boris, please take this via the Xen tree (Thomas asked us to do so)
Sure, but we will need to rebase to the latest bits, so you will have to
explain yourself to Linus ;-)
-boris
On 20/08/18 18:56, Boris Ostrovsky wrote:
> On 08/20/2018 11:24 AM, Juergen Gross wrote:
>> Commit 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in
>> init_hypervisor_platform()") moved the mapping of the shared info area
>> before pagetable_init(). This breaks booting as 32-bit PV guest as the
>> use of set_fixmap isn't possible at this time on 32-bit.
>>
>> This can be worked around by populating the needed PMD on 32-bit
>> kernel earlier.
>>
>> In order not to reimplement populate_extra_pte() using extend_brk()
>> for allocating new page tables extend alloc_low_pages() to do that in
>> case the early page table pool is not yet available.
>>
>> Fixes: 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in init_hypervisor_platform()")
>> Signed-off-by: Juergen Gross <[email protected]>
>> Reviewed-by: Thomas Gleixner <[email protected]>
>> ---
>> Resending with corrected Fixes: tag
>> Boris, please take this via the Xen tree (Thomas asked us to do so)
>
>
> Sure, but we will need to rebase to the latest bits, so you will have to
> explain yourself to Linus ;-)
NP for me. At least I hope so. :-)
Juergen
On 08/20/2018 11:24 AM, Juergen Gross wrote:
> Commit 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in
> init_hypervisor_platform()") moved the mapping of the shared info area
> before pagetable_init(). This breaks booting as 32-bit PV guest as the
> use of set_fixmap isn't possible at this time on 32-bit.
>
> This can be worked around by populating the needed PMD on 32-bit
> kernel earlier.
>
> In order not to reimplement populate_extra_pte() using extend_brk()
> for allocating new page tables extend alloc_low_pages() to do that in
> case the early page table pool is not yet available.
>
> Fixes: 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in init_hypervisor_platform()")
> Signed-off-by: Juergen Gross <[email protected]>
> Reviewed-by: Thomas Gleixner <[email protected]>
> ---
> Resending with corrected Fixes: tag
> Boris, please take this via the Xen tree (Thomas asked us to do so)
Applied to for-linus-19b.
-boris