Mailing List Archive

commit c182e89d0b341d2efc930c2e1211d3e866c0effb
Author: Andrew Cooper <andrew.cooper3@citrix.com>
AuthorDate: Mon Nov 29 19:01:50 2021 +0000
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Thu Dec 2 20:02:55 2021 +0000

x86/boot: Drop xen_virt_end

The calculation in __start_xen() for xen_virt_end is an opencoding of
ROUNDUP(_end, 2M). This is __2M_rwdata_end as provided by the linker script.

This corrects the bound calculations in arch_livepatch_init() and
update_xen_mappings() to not enforce 2M alignment when Xen is not compiled
with CONFIG_XEN_ALIGN_2M.

Furthermore, since 52975142d154 ("x86/boot: Create the l2_xenmap[] mappings
dynamically"), there have not been extraneous mappings to delete, meaning that
the call to destroy_xen_mappings() has been a no-op.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
xen/arch/x86/livepatch.c | 3 ++-
xen/arch/x86/mm.c | 3 ++-
xen/arch/x86/setup.c | 6 ------
xen/include/asm-x86/x86_64/page.h | 2 --
4 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/livepatch.c b/xen/arch/x86/livepatch.c
index 49f0d902e5..d056b1ed8b 100644
--- a/xen/arch/x86/livepatch.c
+++ b/xen/arch/x86/livepatch.c
@@ -17,6 +17,7 @@
#include <asm/fixmap.h>
#include <asm/nmi.h>
#include <asm/livepatch.h>
+#include <asm/setup.h>

static bool has_active_waitqueue(const struct vm_event_domain *ved)
{
@@ -343,7 +344,7 @@ void __init arch_livepatch_init(void)
{
void *start, *end;

- start = (void *)xen_virt_end;
+ start = (void *)__2M_rwdata_end;
end = (void *)(XEN_VIRT_END - FIXADDR_X_SIZE - NR_CPUS * PAGE_SIZE);

BUG_ON(end <= start);
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 4d799032dc..4a9ac8d5e6 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -787,7 +787,8 @@ static int update_xen_mappings(unsigned long mfn, unsigned int cacheattr)
{
int err = 0;
bool alias = mfn >= PFN_DOWN(xen_phys_start) &&
- mfn < PFN_UP(xen_phys_start + xen_virt_end - XEN_VIRT_START);
+ mfn < PFN_UP(xen_phys_start + (unsigned long)__2M_rwdata_end -
+ XEN_VIRT_START);
unsigned long xen_va =
XEN_VIRT_START + ((mfn - PFN_DOWN(xen_phys_start)) << PAGE_SHIFT);

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 6613e56a21..0e0e706404 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -136,8 +136,6 @@ cpumask_t __read_mostly cpu_present_map;

unsigned long __read_mostly xen_phys_start;

-unsigned long __read_mostly xen_virt_end;
-
char __section(".bss.stack_aligned") __aligned(STACK_SIZE)
cpu0_stack[STACK_SIZE];

@@ -1573,10 +1571,6 @@ void __init noreturn __start_xen(unsigned long mbi_p)
}
#endif

- xen_virt_end = ((unsigned long)_end + (1UL << L2_PAGETABLE_SHIFT) - 1) &
- ~((1UL << L2_PAGETABLE_SHIFT) - 1);
- destroy_xen_mappings(xen_virt_end, XEN_VIRT_START + BOOTSTRAP_MAP_BASE);
-
/*
* If not using 2M mappings to gain suitable pagetable permissions
* directly from the relocation above, remap the code/data
diff --git a/xen/include/asm-x86/x86_64/page.h b/xen/include/asm-x86/x86_64/page.h
index f9faf7f383..cb1db107c4 100644
--- a/xen/include/asm-x86/x86_64/page.h
+++ b/xen/include/asm-x86/x86_64/page.h
@@ -23,8 +23,6 @@ static inline unsigned long canonicalise_addr(unsigned long addr)

#include <xen/pdx.h>

-extern unsigned long xen_virt_end;
-
/*
* Note: These are solely for the use by page_{get,set}_owner(), and
* therefore don't need to handle the XEN_VIRT_{START,END} range.
--
generated by git-patchbot for /home/xen/git/xen.git#staging