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dump: Update correct kdump phys_base field for AArch64

PATCH In review Wei Huang 3 participants 3 messages Mar 9, 2018 – Mar 12, 2018

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Wei Huang

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#0 lore raw

PATCH 1/1 dump: Update correct kdump phys_base field for AArch64

For guest kernel that supports KASLR, the load address can change every time when guest VM runs. To find the physical base address correctly, current QEMU dump searches VMCOREINFO for the string "NUMBER(phys_base)=". However this string pattern is only available on x86_64. AArch64 uses a different field, called "NUMBER(PHYS_OFFSET)=". This patch makes sure QEMU dump uses the correct string on AArch64.

---
 dump.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)
dump.c +11 -3
index 097e60b..6bdb0db 100644
@@ -1609,10 +1609,18 @@ static void vmcoreinfo_update_phys_base(DumpState *s)
 
     lines = g_strsplit((char *)vmci, "\n", -1);
     for (i = 0; lines[i]; i++) {
-        if (g_str_has_prefix(lines[i], "NUMBER(phys_base)=")) {
-            if (qemu_strtou64(lines[i] + 18, NULL, 16,
+        const char *prefix = NULL;
+
+        if (s->dump_info.d_machine == EM_X86_64) {
+            prefix = "NUMBER(phys_base)=";
+        } else if (s->dump_info.d_machine == EM_AARCH64) {
+            prefix = "NUMBER(PHYS_OFFSET)=";
+        }
+
+        if (prefix && g_str_has_prefix(lines[i], prefix)) {
+            if (qemu_strtou64(lines[i] + strlen(prefix), NULL, 16,
                               &phys_base) < 0) {
-                warn_report("Failed to read NUMBER(phys_base)=");
+                warn_report("Failed to read %s", prefix);
             } else {
                 s->dump_info.phys_base = phys_base;
             }
Signature · 1 line
1.8.3.1
Reviewed-by on v1 1/1
#1 lore raw

Hi

Quoted 8 lines · Wei Huang

For guest kernel that supports KASLR, the load address can change every time when guest VM runs. To find the physical base address correctly, current QEMU dump searches VMCOREINFO for the string "NUMBER(phys_base)=". However this string pattern is only available on x86_64. AArch64 uses a different field, called "NUMBER(PHYS_OFFSET)=". This patch makes sure QEMU dump uses the correct string on AArch64.

Quoted 33 lines
---
 dump.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)
dump.c +11 -4
index 097e60b..6bdb0db 100644
@@ -1609,10 +1609,18 @@ static void vmcoreinfo_update_phys_base(DumpState *s)
 
     lines = g_strsplit((char *)vmci, "\n", -1);
     for (i = 0; lines[i]; i++) {
-        if (g_str_has_prefix(lines[i], "NUMBER(phys_base)=")) {
-            if (qemu_strtou64(lines[i] + 18, NULL, 16,
+        const char *prefix = NULL;
+
+        if (s->dump_info.d_machine == EM_X86_64) {
+            prefix = "NUMBER(phys_base)=";
+        } else if (s->dump_info.d_machine == EM_AARCH64) {
+            prefix = "NUMBER(PHYS_OFFSET)=";
+        }
+
+        if (prefix && g_str_has_prefix(lines[i], prefix)) {
+            if (qemu_strtou64(lines[i] + strlen(prefix), NULL, 16,
                               &phys_base) < 0) {
-                warn_report("Failed to read NUMBER(phys_base)=");
+                warn_report("Failed to read %s", prefix);
             } else {
                 s->dump_info.phys_base = phys_base;
             }
--

1.8.3.1

#2 lore raw
Quoted 10 lines · Marc-André Lureau

Hi

Quoted 7 lines · Wei Huang

For guest kernel that supports KASLR, the load address can change every time when guest VM runs. To find the physical base address correctly, current QEMU dump searches VMCOREINFO for the string "NUMBER(phys_base)=". However this string pattern is only available on x86_64. AArch64 uses a different field, called "NUMBER(PHYS_OFFSET)=". This patch makes sure QEMU dump uses the correct string on AArch64.

Quoted 3 lines
Quoted 1 line

Thanks; applied to target-arm.next for 2.12.

-- PMM