From: Marc Zyngier <maz@kernel.org>
Date: Wed, 13 Oct 2021 12:03:38 +0000 (+0100)
Subject: KVM: arm64: pkvm: Make the ERR/ERX*_EL1 registers RAZ/WI
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8ffb41888334c1247bd9b4d6ff6c092a90e8d0b8;p=linux.git

KVM: arm64: pkvm: Make the ERR/ERX*_EL1 registers RAZ/WI

The ERR*/ERX* registers should be handled as RAZ/WI, and there
should be no need to involve EL1 for that.

Add a helper that handles such registers, and repaint the sysreg
table to declare these registers as RAZ/WI.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20211013120346.2926621-4-maz@kernel.org
---

diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index f125d6a52880a..042a1c0be7e0e 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -248,6 +248,16 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
 	return pvm_read_id_reg(vcpu, reg_to_encoding(r));
 }
 
+/* Handler to RAZ/WI sysregs */
+static bool pvm_access_raz_wi(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			      const struct sys_reg_desc *r)
+{
+	if (!p->is_write)
+		p->regval = 0;
+
+	return true;
+}
+
 /*
  * Accessor for AArch32 feature id registers.
  *
@@ -270,9 +280,7 @@ static bool pvm_access_id_aarch32(struct kvm_vcpu *vcpu,
 	BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1),
 		     PVM_ID_AA64PFR0_RESTRICT_UNSIGNED) > ID_AA64PFR0_ELx_64BIT_ONLY);
 
-	/* Use 0 for architecturally "unknown" values. */
-	p->regval = 0;
-	return true;
+	return pvm_access_raz_wi(vcpu, p, r);
 }
 
 /*
@@ -301,6 +309,9 @@ static bool pvm_access_id_aarch64(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 }
 
+/* Mark the specified system register as Read-As-Zero/Write-Ignored */
+#define RAZ_WI(REG) { SYS_DESC(REG), .access = pvm_access_raz_wi }
+
 /* Mark the specified system register as not being handled in hyp. */
 #define HOST_HANDLED(REG) { SYS_DESC(REG), .access = NULL }
 
@@ -388,14 +399,14 @@ static const struct sys_reg_desc pvm_sys_reg_descs[] = {
 	HOST_HANDLED(SYS_AFSR1_EL1),
 	HOST_HANDLED(SYS_ESR_EL1),
 
-	HOST_HANDLED(SYS_ERRIDR_EL1),
-	HOST_HANDLED(SYS_ERRSELR_EL1),
-	HOST_HANDLED(SYS_ERXFR_EL1),
-	HOST_HANDLED(SYS_ERXCTLR_EL1),
-	HOST_HANDLED(SYS_ERXSTATUS_EL1),
-	HOST_HANDLED(SYS_ERXADDR_EL1),
-	HOST_HANDLED(SYS_ERXMISC0_EL1),
-	HOST_HANDLED(SYS_ERXMISC1_EL1),
+	RAZ_WI(SYS_ERRIDR_EL1),
+	RAZ_WI(SYS_ERRSELR_EL1),
+	RAZ_WI(SYS_ERXFR_EL1),
+	RAZ_WI(SYS_ERXCTLR_EL1),
+	RAZ_WI(SYS_ERXSTATUS_EL1),
+	RAZ_WI(SYS_ERXADDR_EL1),
+	RAZ_WI(SYS_ERXMISC0_EL1),
+	RAZ_WI(SYS_ERXMISC1_EL1),
 
 	HOST_HANDLED(SYS_TFSR_EL1),
 	HOST_HANDLED(SYS_TFSRE0_EL1),