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From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	Anshuman Khandual <anshuman.linux@gmail.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Christoph Hellwig <hch@lst.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Mike Anderson <andmike@linux.ibm.com>,
	Paul Mackerras <paulus@samba.org>, Ram Pai <linuxram@us.ibm.com>,
	Claudio Carvalho <cclaudio@linux.ibm.com>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>
Subject: [PATCH v2 08/13] powerpc/pseries/svm: Unshare all pages before kexecing a new kernel
Date: Sat, 13 Jul 2019 03:00:18 -0300	[thread overview]
Message-ID: <20190713060023.8479-9-bauerman@linux.ibm.com> (raw)
In-Reply-To: <20190713060023.8479-1-bauerman@linux.ibm.com>

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     | 6 ++++++
 arch/powerpc/kernel/machine_kexec_64.c    | 8 ++++++++
 3 files changed, 15 insertions(+)

diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index c7513bbadf57..ab4f756cb91c 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -29,5 +29,6 @@
 #define UV_UNSHARE_PAGE			0xF134
 #define UV_PAGE_INVAL			0xF138
 #define UV_SVM_TERMINATE		0xF13C
+#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 f7418b663a0e..80d4beaf61b8 100644
--- a/arch/powerpc/include/asm/ultravisor.h
+++ b/arch/powerpc/include/asm/ultravisor.h
@@ -106,6 +106,12 @@ static inline int uv_unshare_page(u64 pfn, u64 npages)
 	return ucall(UV_UNSHARE_PAGE, retbuf, pfn, npages);
 }
 
+static inline int uv_unshare_all_pages(void)
+{
+	unsigned long retbuf[UCALL_BUFSIZE];
+
+	return ucall(UV_UNSHARE_ALL_PAGES, retbuf);
+}
 #endif /* !__ASSEMBLY__ */
 
 #endif	/* _ASM_POWERPC_ULTRAVISOR_H */
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 75692c327ba0..b3d87d32e8f7 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -31,6 +31,7 @@
 #include <asm/smp.h>
 #include <asm/hw_breakpoint.h>
 #include <asm/asm-prototypes.h>
+#include <asm/ultravisor.h>
 
 int default_machine_kexec_prepare(struct kimage *image)
 {
@@ -329,6 +330,13 @@ 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);


  parent reply	other threads:[~2019-07-13  6:01 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-13  6:00 [PATCH v2 00/13] Secure Virtual Machine Enablement Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 01/13] powerpc/pseries: Introduce option to build secure virtual machines Thiago Jung Bauermann
2019-07-13  6:00 ` [RFC PATCH v2 02/13] powerpc: Add support for adding an ESM blob to the zImage wrapper Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 03/13] powerpc/prom_init: Add the ESM call to prom_init Thiago Jung Bauermann
2019-07-18  8:11   ` Alexey Kardashevskiy
2019-07-18 19:58     ` Segher Boessenkool
2019-07-18 21:28       ` Thiago Jung Bauermann
2019-07-19  0:09         ` Alexey Kardashevskiy
2019-07-19  0:48           ` Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 04/13] powerpc/pseries/svm: Add helpers for UV_SHARE_PAGE and UV_UNSHARE_PAGE Thiago Jung Bauermann
2019-07-18  8:13   ` Alexey Kardashevskiy
2019-07-18 20:12     ` Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 05/13] powerpc/pseries: Add and use LPPACA_SIZE constant Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 06/13] powerpc/pseries/svm: Use shared memory for LPPACA structures Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 07/13] powerpc/pseries/svm: Use shared memory for Debug Trace Log (DTL) Thiago Jung Bauermann
2019-07-13  6:00 ` Thiago Jung Bauermann [this message]
2019-07-13  6:00 ` [PATCH v2 09/13] powerpc/pseries/svm: Export guest SVM status to user space via sysfs Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 10/13] powerpc/pseries/svm: Disable doorbells in SVM guests Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 11/13] powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 12/13] powerpc/pseries/svm: Force SWIOTLB for " Thiago Jung Bauermann
2019-07-13  6:00 ` [PATCH v2 13/13] powerpc/configs: Enable secure guest support in pseries and ppc64 defconfigs Thiago Jung Bauermann

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