[v9] Support kdump with LUKS encryption by reusing LUKS volume keys

[PATCH v9 6/8] Revert "x86/mm: Remove unused __set_memory_prot()"

Posted by Coiby Xu 6 months, 2 weeks ago

This reverts commit 693bbf2a50447353c6a47961e6a7240a823ace02 as kdump
LUKS support (CONFIG_CRASH_DM_CRYPT) depends on __set_memory_prot.

Signed-off-by: Coiby Xu <coxu@redhat.com>
---
 arch/x86/include/asm/set_memory.h |  1 +
 arch/x86/mm/pat/set_memory.c      | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 8d9f1c9aaa4c..023994fe6115 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -37,6 +37,7 @@ int set_memory_rox(unsigned long addr, int numpages);
  * The caller is required to take care of these.
  */
 
+int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot);
 int _set_memory_uc(unsigned long addr, int numpages);
 int _set_memory_wc(unsigned long addr, int numpages);
 int _set_memory_wt(unsigned long addr, int numpages);
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index def3d9284254..df7502ad165c 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2148,6 +2148,19 @@ static inline int cpa_clear_pages_array(struct page **pages, int numpages,
 		CPA_PAGES_ARRAY, pages);
 }
 
+/*
+ * __set_memory_prot is an internal helper for callers that have been passed
+ * a pgprot_t value from upper layers and a reservation has already been taken.
+ * If you want to set the pgprot to a specific page protocol, use the
+ * set_memory_xx() functions.
+ */
+int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot)
+{
+	return change_page_attr_set_clr(&addr, numpages, prot,
+					__pgprot(~pgprot_val(prot)), 0, 0,
+					NULL);
+}
+
 int _set_memory_uc(unsigned long addr, int numpages)
 {
 	/*
-- 
2.49.0

Re: [PATCH v9 6/8] Revert "x86/mm: Remove unused __set_memory_prot()"

Posted by Andrew Morton 6 months, 2 weeks ago

On Fri,  2 May 2025 09:12:40 +0800 Coiby Xu <coxu@redhat.com> wrote:

> This reverts commit 693bbf2a50447353c6a47961e6a7240a823ace02 as kdump
> LUKS support (CONFIG_CRASH_DM_CRYPT) depends on __set_memory_prot.
> 

x86_64 allmodconfig:

In file included from drivers/gpu/drm/i915/gt/intel_ggtt.c:6:
./arch/x86/include/asm/set_memory.h:40:57: error: unknown type name 'pgprot_t'
   40 | int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot);
      |                                                         ^~~~~~~~

I did this:


From: Andrew Morton <akpm@linux-foundation.org>
Subject: revert-x86-mm-remove-unused-__set_memory_prot-fix
Date: Sat May  3 11:38:32 PM PDT 2025

x86 set_memory.h needs pgtable_types.h for pgprot_t.  Obtain it via the
higher-level pgtable.h.

Cc: Baoquan He <bhe@redhat.com>
Cc: Coiby Xu <coxu@redhat.com>
Cc: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Jan Pazdziora <jpazdziora@redhat.com>
Cc: Liu Pingfan <kernelfans@gmail.com>
Cc: Milan Broz <gmazyland@gmail.com>
Cc: Ondrej Kozina <okozina@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/include/asm/set_memory.h |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/include/asm/set_memory.h~revert-x86-mm-remove-unused-__set_memory_prot-fix
+++ a/arch/x86/include/asm/set_memory.h
@@ -4,6 +4,7 @@
 
 #include <asm/page.h>
 #include <asm-generic/set_memory.h>
+#include <asm/pgtable.h>
 
 #define set_memory_rox set_memory_rox
 int set_memory_rox(unsigned long addr, int numpages);
_

Re: [PATCH v9 6/8] Revert "x86/mm: Remove unused __set_memory_prot()"

Posted by Coiby Xu 6 months, 1 week ago

On Sat, May 03, 2025 at 11:46:05PM -0700, Andrew Morton wrote:
>On Fri,  2 May 2025 09:12:40 +0800 Coiby Xu <coxu@redhat.com> wrote:
>
>> This reverts commit 693bbf2a50447353c6a47961e6a7240a823ace02 as kdump
>> LUKS support (CONFIG_CRASH_DM_CRYPT) depends on __set_memory_prot.
>>
>
>x86_64 allmodconfig:
>
>In file included from drivers/gpu/drm/i915/gt/intel_ggtt.c:6:
>./arch/x86/include/asm/set_memory.h:40:57: error: unknown type name 'pgprot_t'
>   40 | int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot);
>      |                                                         ^~~~~~~~
>
>I did this:
>
>
>From: Andrew Morton <akpm@linux-foundation.org>
>Subject: revert-x86-mm-remove-unused-__set_memory_prot-fix
>Date: Sat May  3 11:38:32 PM PDT 2025
>
>x86 set_memory.h needs pgtable_types.h for pgprot_t.  Obtain it via the
>higher-level pgtable.h.
>
>Cc: Baoquan He <bhe@redhat.com>
>Cc: Coiby Xu <coxu@redhat.com>
>Cc: "Daniel P. Berrange" <berrange@redhat.com>
>Cc: Dave Hansen <dave.hansen@intel.com>
>Cc: Dave Young <dyoung@redhat.com>
>Cc: Jan Pazdziora <jpazdziora@redhat.com>
>Cc: Liu Pingfan <kernelfans@gmail.com>
>Cc: Milan Broz <gmazyland@gmail.com>
>Cc: Ondrej Kozina <okozina@redhat.com>
>Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
>Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>---
>
> arch/x86/include/asm/set_memory.h |    1 +
> 1 file changed, 1 insertion(+)
>
>--- a/arch/x86/include/asm/set_memory.h~revert-x86-mm-remove-unused-__set_memory_prot-fix
>+++ a/arch/x86/include/asm/set_memory.h
>@@ -4,6 +4,7 @@
>
> #include <asm/page.h>
> #include <asm-generic/set_memory.h>
>+#include <asm/pgtable.h>
>
> #define set_memory_rox set_memory_rox
> int set_memory_rox(unsigned long addr, int numpages);
>_

Thanks for catching this issue and providing a clean fix! I'll make sure
future patches pass allmodconfig. And also thanks for pulling the patch
set into -mm tree!

-- 
Best regards,
Coiby