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powerpc/pseries/svm: Unshare all pages before kexecing a new kernel

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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
This commit is contained in:
Ram Pai
2019-08-19 23:13:20 -03:00
committed by Michael Ellerman
parent d5394c059d
commit 256ba2c168
3 changed files with 15 additions and 0 deletions
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9
arch/powerpc/kernel/machine_kexec_64.c
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@@ -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);