[v4,10/16] powerpc/pseries/svm: Unshare all pages before kexecing a new kernel
diff mbox series

Message ID 20190820021326.6884-11-bauerman@linux.ibm.com
State Accepted
Commit 256ba2c1689efd4f5383cf7ebe2f9970c198b79d
Headers show
Series
  • Secure Virtual Machine Enablement
Related show

Checks

Context Check Description
snowpatch_ozlabs/checkpatch warning total: 0 errors, 1 warnings, 0 checks, 36 lines checked
snowpatch_ozlabs/apply_patch success Successfully applied on branch next (c9633332103e55bc73d80d07ead28b95a22a85a3)

Commit Message

Thiago Jung Bauermann Aug. 20, 2019, 2:13 a.m. UTC
From: Ram Pai <linuxram@us.ibm.com>

A new kernel deserves a clean slate. Any pages shared with the hypervisor
is unshared before invoking the new kernel. However there are exceptions.
If the new kernel is invoked to dump the current kernel, or if there is a
explicit request to preserve the state of the current kernel, unsharing
of pages is skipped.

NOTE: While testing crashkernel, make sure at least 256M is reserved for
crashkernel. Otherwise SWIOTLB allocation will fail and crash kernel will
fail to boot.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/powerpc/include/asm/ultravisor-api.h | 1 +
 arch/powerpc/include/asm/ultravisor.h     | 5 +++++
 arch/powerpc/kernel/machine_kexec_64.c    | 9 +++++++++
 3 files changed, 15 insertions(+)

Patch
diff mbox series

diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index 142b0576b89f..7e69c364bde0 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -24,5 +24,6 @@ 
 #define UV_ESM				0xF110
 #define UV_SHARE_PAGE			0xF130
 #define UV_UNSHARE_PAGE			0xF134
+#define UV_UNSHARE_ALL_PAGES		0xF140
 
 #endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h
index a930aec8c1e3..e6f8a2b96694 100644
--- a/arch/powerpc/include/asm/ultravisor.h
+++ b/arch/powerpc/include/asm/ultravisor.h
@@ -21,4 +21,9 @@  static inline int uv_unshare_page(u64 pfn, u64 npages)
 	return ucall_norets(UV_UNSHARE_PAGE, pfn, npages);
 }
 
+static inline int uv_unshare_all_pages(void)
+{
+	return ucall_norets(UV_UNSHARE_ALL_PAGES);
+}
+
 #endif	/* _ASM_POWERPC_ULTRAVISOR_H */
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 18481b0e2788..04a7cba58eff 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -29,6 +29,8 @@ 
 #include <asm/smp.h>
 #include <asm/hw_breakpoint.h>
 #include <asm/asm-prototypes.h>
+#include <asm/svm.h>
+#include <asm/ultravisor.h>
 
 int default_machine_kexec_prepare(struct kimage *image)
 {
@@ -327,6 +329,13 @@  void default_machine_kexec(struct kimage *image)
 #ifdef CONFIG_PPC_PSERIES
 	kexec_paca.lppaca_ptr = NULL;
 #endif
+
+	if (is_secure_guest() && !(image->preserve_context ||
+				   image->type == KEXEC_TYPE_CRASH)) {
+		uv_unshare_all_pages();
+		printk("kexec: Unshared all shared pages.\n");
+	}
+
 	paca_ptrs[kexec_paca.paca_index] = &kexec_paca;
 
 	setup_paca(&kexec_paca);