From 256ba2c1689efd4f5383cf7ebe2f9970c198b79d Mon Sep 17 00:00:00 2001 From: Ram Pai Date: Mon, 19 Aug 2019 23:13:20 -0300 Subject: [PATCH] powerpc/pseries/svm: Unshare all pages before kexecing a new kernel 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 Signed-off-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190820021326.6884-11-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(+) diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h index 0f5b2d718bfc..4fcda1d5793d 100644 --- a/arch/powerpc/include/asm/ultravisor-api.h +++ b/arch/powerpc/include/asm/ultravisor-api.h @@ -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 */ diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h index e5c8413de06f..b1bc2e043ed4 100644 --- a/arch/powerpc/include/asm/ultravisor.h +++ b/arch/powerpc/include/asm/ultravisor.h @@ -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 */ 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 #include #include +#include +#include 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);