diff mbox series

[2/6] KVM: arm64: Handle all ID registers trapped for a protected VM

Message ID 20220609121223.2551-3-will@kernel.org (mailing list archive)
State New, archived
Headers show
Series KVM/arm64: Minor/trivial fixes from pKVM mega-patch | expand

Commit Message

Will Deacon June 9, 2022, 12:12 p.m. UTC 
From: Marc Zyngier <maz@kernel.org>

A protected VM accessing ID_AA64ISAR2_EL1 gets punished with an UNDEF,
while it really should only get a zero back if the register is not
handled by the hypervisor emulation (as mandated by the architecture).

Introduce all the missing ID registers (including the unallocated ones),
and have them to return 0.

Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/nvhe/sys_regs.c | 42 ++++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 8 deletions(-)

Comments

Reiji Watanabe June 14, 2022, 5:57 a.m. UTC | #1 
On Thu, Jun 9, 2022 at 5:12 AM Will Deacon <will@kernel.org> wrote:
>
> From: Marc Zyngier <maz@kernel.org>
>
> A protected VM accessing ID_AA64ISAR2_EL1 gets punished with an UNDEF,
> while it really should only get a zero back if the register is not
> handled by the hypervisor emulation (as mandated by the architecture).
>
> Introduce all the missing ID registers (including the unallocated ones),
> and have them to return 0.
>
> Reported-by: Will Deacon <will@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>
diff mbox series

Patch

diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index b6d86e423319..35a4331ba5f3 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -243,15 +243,9 @@  u64 pvm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
 	case SYS_ID_AA64MMFR2_EL1:
 		return get_pvm_id_aa64mmfr2(vcpu);
 	default:
-		/*
-		 * Should never happen because all cases are covered in
-		 * pvm_sys_reg_descs[].
-		 */
-		WARN_ON(1);
-		break;
+		/* Unhandled ID register, RAZ */
+		return 0;
 	}
-
-	return 0;
 }
 
 static u64 read_id_reg(const struct kvm_vcpu *vcpu,
@@ -332,6 +326,16 @@  static bool pvm_gic_read_sre(struct kvm_vcpu *vcpu,
 /* Mark the specified system register as an AArch64 feature id register. */
 #define AARCH64(REG) { SYS_DESC(REG), .access = pvm_access_id_aarch64 }
 
+/*
+ * sys_reg_desc initialiser for architecturally unallocated cpufeature ID
+ * register with encoding Op0=3, Op1=0, CRn=0, CRm=crm, Op2=op2
+ * (1 <= crm < 8, 0 <= Op2 < 8).
+ */
+#define ID_UNALLOCATED(crm, op2) {			\
+	Op0(3), Op1(0), CRn(0), CRm(crm), Op2(op2),	\
+	.access = pvm_access_id_aarch64,		\
+}
+
 /* Mark the specified system register as Read-As-Zero/Write-Ignored */
 #define RAZ_WI(REG) { SYS_DESC(REG), .access = pvm_access_raz_wi }
 
@@ -375,24 +379,46 @@  static const struct sys_reg_desc pvm_sys_reg_descs[] = {
 	AARCH32(SYS_MVFR0_EL1),
 	AARCH32(SYS_MVFR1_EL1),
 	AARCH32(SYS_MVFR2_EL1),
+	ID_UNALLOCATED(3,3),
 	AARCH32(SYS_ID_PFR2_EL1),
 	AARCH32(SYS_ID_DFR1_EL1),
 	AARCH32(SYS_ID_MMFR5_EL1),
+	ID_UNALLOCATED(3,7),
 
 	/* AArch64 ID registers */
 	/* CRm=4 */
 	AARCH64(SYS_ID_AA64PFR0_EL1),
 	AARCH64(SYS_ID_AA64PFR1_EL1),
+	ID_UNALLOCATED(4,2),
+	ID_UNALLOCATED(4,3),
 	AARCH64(SYS_ID_AA64ZFR0_EL1),
+	ID_UNALLOCATED(4,5),
+	ID_UNALLOCATED(4,6),
+	ID_UNALLOCATED(4,7),
 	AARCH64(SYS_ID_AA64DFR0_EL1),
 	AARCH64(SYS_ID_AA64DFR1_EL1),
+	ID_UNALLOCATED(5,2),
+	ID_UNALLOCATED(5,3),
 	AARCH64(SYS_ID_AA64AFR0_EL1),
 	AARCH64(SYS_ID_AA64AFR1_EL1),
+	ID_UNALLOCATED(5,6),
+	ID_UNALLOCATED(5,7),
 	AARCH64(SYS_ID_AA64ISAR0_EL1),
 	AARCH64(SYS_ID_AA64ISAR1_EL1),
+	AARCH64(SYS_ID_AA64ISAR2_EL1),
+	ID_UNALLOCATED(6,3),
+	ID_UNALLOCATED(6,4),
+	ID_UNALLOCATED(6,5),
+	ID_UNALLOCATED(6,6),
+	ID_UNALLOCATED(6,7),
 	AARCH64(SYS_ID_AA64MMFR0_EL1),
 	AARCH64(SYS_ID_AA64MMFR1_EL1),
 	AARCH64(SYS_ID_AA64MMFR2_EL1),
+	ID_UNALLOCATED(7,3),
+	ID_UNALLOCATED(7,4),
+	ID_UNALLOCATED(7,5),
+	ID_UNALLOCATED(7,6),
+	ID_UNALLOCATED(7,7),
 
 	/* Scalable Vector Registers are restricted. */