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| author | Fabiano Rosas <farosas@linux.ibm.com> | 2022-06-24 11:27:12 -0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-06-29 19:21:33 +1000 |
| commit | f5c847ea19d323974d6f7c7e9fa4858ce0727096 (patch) | |
| tree | cca4263a8f411bbd2356658781fcee06052550a1 | |
| parent | 0df01238b8aa300cbc736e7ec433d201a76036f3 (diff) | |
| download | lwn-f5c847ea19d323974d6f7c7e9fa4858ce0727096.tar.gz lwn-f5c847ea19d323974d6f7c7e9fa4858ce0727096.zip | |
KVM: PPC: Align pt_regs in kvm_vcpu_arch structure
The H_ENTER_NESTED hypercall receives as second parameter the address
of a region of memory containing the values for the nested guest
privileged registers. We currently use the pt_regs structure contained
within kvm_vcpu_arch for that end.
Most hypercalls that receive a memory address expect that region to
not cross a 4K page boundary. We would want H_ENTER_NESTED to follow
the same pattern so this patch ensures the pt_regs structure sits
within a page.
Note: the pt_regs structure is currently 384 bytes in size, so
aligning to 512 is sufficient to ensure it will not cross a 4K page
and avoids punching too big a hole in struct kvm_vcpu_arch.
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Murilo Opsfelder Araújo <muriloo@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220624142712.790491-1-farosas@linux.ibm.com
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index eeba679802cf..c2b003550dc9 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -523,7 +523,11 @@ struct kvm_vcpu_arch { struct kvmppc_book3s_shadow_vcpu *shadow_vcpu; #endif - struct pt_regs regs; + /* + * This is passed along to the HV via H_ENTER_NESTED. Align to + * prevent it crossing a real 4K page. + */ + struct pt_regs regs __aligned(512); struct thread_fp_state fp; |