powerpc/pseries/svm: Unshare all pages before kexecing a new kernel (256ba2c1) · Commits · 戴 / test

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> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190820021326.6884-11-bauerman@linux.ibm.com

arch/powerpc/include/asm/ultravisor-api.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -28,5 +28,6 @@
		#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 */

arch/powerpc/include/asm/ultravisor.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -41,4 +41,9 @@ 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 */

arch/powerpc/kernel/machine_kexec_64.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -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);

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