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From: Andrew Jones <drjones@redhat.com>
To: kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, xu910121@sina.com, Dave.Martin@arm.com
Subject: [PATCH 1/3] KVM: arm64: Don't hide ID registers from userspace
Date: Thu, 29 Oct 2020 21:11:03 +0100	[thread overview]
Message-ID: <20201029201105.101910-2-drjones@redhat.com> (raw)
In-Reply-To: <20201029201105.101910-1-drjones@redhat.com>

ID registers are RAZ until they've been allocated a purpose, but
that doesn't mean they should be removed from the KVM_GET_REG_LIST
list. So far we only have one register, SYS_ID_AA64ZFR0_EL1, that
is hidden from userspace when its function is not present. Removing
the userspace visibility checks is enough to reexpose it, as it
already behaves as RAZ when the function is not present.

Fixes: 73433762fcae ("KVM: arm64/sve: System register context switch and access support")
Reported-by: 张东旭 <xu910121@sina.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 arch/arm64/kvm/sys_regs.c | 18 +-----------------
 1 file changed, 1 insertion(+), 17 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d9117bc56237..d24e66ee59b3 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1195,16 +1195,6 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
 	return REG_HIDDEN_USER | REG_HIDDEN_GUEST;
 }
 
-/* Visibility overrides for SVE-specific ID registers */
-static unsigned int sve_id_visibility(const struct kvm_vcpu *vcpu,
-				      const struct sys_reg_desc *rd)
-{
-	if (vcpu_has_sve(vcpu))
-		return 0;
-
-	return REG_HIDDEN_USER;
-}
-
 /* Generate the emulated ID_AA64ZFR0_EL1 value exposed to the guest */
 static u64 guest_id_aa64zfr0_el1(const struct kvm_vcpu *vcpu)
 {
@@ -1231,9 +1221,6 @@ static int get_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
 {
 	u64 val;
 
-	if (WARN_ON(!vcpu_has_sve(vcpu)))
-		return -ENOENT;
-
 	val = guest_id_aa64zfr0_el1(vcpu);
 	return reg_to_user(uaddr, &val, reg->id);
 }
@@ -1246,9 +1233,6 @@ static int set_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
 	int err;
 	u64 val;
 
-	if (WARN_ON(!vcpu_has_sve(vcpu)))
-		return -ENOENT;
-
 	err = reg_from_user(&val, uaddr, id);
 	if (err)
 		return err;
@@ -1518,7 +1502,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	ID_SANITISED(ID_AA64PFR1_EL1),
 	ID_UNALLOCATED(4,2),
 	ID_UNALLOCATED(4,3),
-	{ SYS_DESC(SYS_ID_AA64ZFR0_EL1), access_id_aa64zfr0_el1, .get_user = get_id_aa64zfr0_el1, .set_user = set_id_aa64zfr0_el1, .visibility = sve_id_visibility },
+	{ SYS_DESC(SYS_ID_AA64ZFR0_EL1), access_id_aa64zfr0_el1, .get_user = get_id_aa64zfr0_el1, .set_user = set_id_aa64zfr0_el1, },
 	ID_UNALLOCATED(4,5),
 	ID_UNALLOCATED(4,6),
 	ID_UNALLOCATED(4,7),
-- 
2.27.0

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  reply	other threads:[~2020-10-29 20:11 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29 20:11 [PATCH 0/3] KVM: arm64: Fix get-reg-list regression Andrew Jones
2020-10-29 20:11 ` Andrew Jones [this message]
2020-10-31 18:09   ` [PATCH 1/3] KVM: arm64: Don't hide ID registers from userspace Marc Zyngier
2020-10-29 20:11 ` [PATCH 2/3] KVM: arm64: Check RAZ visibility in ID register accessors Andrew Jones
2020-10-31 18:23   ` Marc Zyngier
2020-11-02  8:32     ` Andrew Jones
2020-10-29 20:11 ` [PATCH 3/3] KVM: arm64: Remove AA64ZFR0_EL1 accessors Andrew Jones
2020-10-31 18:31   ` Marc Zyngier
2020-10-30  8:15 ` [PATCH 0/3] KVM: arm64: Fix get-reg-list regression 张东旭

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