Commit 45a79e28 authored by Rishabh Bhatnagar's avatar Rishabh Bhatnagar Committed by sanglipeng
Browse files

KVM: x86: move guest_pv_has out of user_access section 

stable inclusion
from stable-v5.10.180
commit fcfe05990a5ce95361dbcae308632861d3c40dfd
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8DDFN

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fcfe05990a5ce95361dbcae308632861d3c40dfd



--------------------------------

From: Paolo Bonzini <pbonzini@redhat.com>

commit 3e067fd8 upstream.

When UBSAN is enabled, the code emitted for the call to guest_pv_has
includes a call to __ubsan_handle_load_invalid_value.  objtool
complains that this call happens with UACCESS enabled; to avoid
the warning, pull the calls to user_access_begin into both arms
of the "if" statement, after the check for guest_pv_has.

Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarRishabh Bhatnagar <risbhat@amazon.com>
Tested-by: default avatarAllen Pais <apais@linux.microsoft.com>
Acked-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarsanglipeng <sanglipeng1@jd.com>
parent 438e6130

arch/x86/kvm/x86.c

+6 −3
Original line number Diff line number Diff line
@@ -3146,9 +3146,6 @@ static void record_steal_time(struct kvm_vcpu *vcpu) 
	}



	st = (struct kvm_steal_time __user *)ghc->hva;

	if (!user_access_begin(st, sizeof(*st)))

		return;



	/*

	 * Doing a TLB flush here, on the guest's behalf, can avoid

	 * expensive IPIs.
@@ -3157,6 +3154,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu) 
		u8 st_preempted = 0;

		int err = -EFAULT;



		if (!user_access_begin(st, sizeof(*st)))

			return;



		asm volatile("1: xchgb %0, %2\n"

			     "xor %1, %1\n"

			     "2:\n"
@@ -3179,6 +3179,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu) 
		if (!user_access_begin(st, sizeof(*st)))

			goto dirty;

	} else {

		if (!user_access_begin(st, sizeof(*st)))

			return;



		unsafe_put_user(0, &st->preempted, out);

		vcpu->arch.st.preempted = 0;

	}