From f5c847ea19d323974d6f7c7e9fa4858ce0727096 Mon Sep 17 00:00:00 2001 From: Fabiano Rosas Date: Fri, 24 Jun 2022 11:27:12 -0300 Subject: [PATCH] KVM: PPC: Align pt_regs in kvm_vcpu_arch structure MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Murilo Opsfelder Araújo Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220624142712.790491-1-farosas@linux.ibm.com --- arch/powerpc/include/asm/kvm_host.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) 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; -- 2.20.1