KVM: MMU: Fix 64-bit paging breakage on x86_32 (8f74d8e1) · Commits · 戴 / test

Fix regression introduced by commit e30d2a170506830d5eef5e9d7990c5aedf1b0a51 KVM: MMU: Optimize guest page table walk On x86_32, get_user() does not support 64-bit values and we fail to build KVM at the point of 64-bit paging. This patch fixes this by using get_user() twice for that condition. Signed-off-by:

Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Reported-by:

Jan Kiszka <jan.kiszka@web.de> Signed-off-by:

Avi Kivity <avi@redhat.com>

arch/x86/kvm/paging_tmpl.h

+15 −1

Original line number	Diff line number	Diff line
		@@ -115,6 +115,20 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
		return access;
		}

		static int FNAME(read_gpte)(pt_element_t pte, pt_element_t __user ptep_user)
		{
		#if defined(CONFIG_X86_32) && (PTTYPE == 64)
		u32 p = (u32 )pte;
		u32 __user p_user = (u32 __user )ptep_user;

		if (unlikely(get_user(*p, p_user)))
		return -EFAULT;
		return get_user(*(p + 1), p_user + 1);
		#else
		return get_user(*pte, ptep_user);
		#endif
		}

		/*
		* Fetch a guest pte for a guest virtual address
		*/
		@@ -185,7 +199,7 @@ walk:
		}

		ptep_user = (pt_element_t __user )((void )host_addr + offset);
		if (unlikely(get_user(pte, ptep_user))) {
		if (unlikely(FNAME(read_gpte)(&pte, ptep_user))) {
		present = false;
		break;
		}

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