linux-kernel - [RFC kvmtool 19/31] arm64: Don't try to set PSTATE for VCPUs belonging to a realm

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Message-Id: <20230127113932.166089-20-suzuki.poulose@arm.com>
Date:   Fri, 27 Jan 2023 11:39:20 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     kvm@...r.kernel.org, kvmarm@...ts.linux.dev
Cc:     suzuki.poulose@....com,
        Alexandru Elisei <alexandru.elisei@....com>,
        Andrew Jones <andrew.jones@...ux.dev>,
        Christoffer Dall <christoffer.dall@....com>,
        Fuad Tabba <tabba@...gle.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        Joey Gouly <Joey.Gouly@....com>, Marc Zyngier <maz@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Quentin Perret <qperret@...gle.com>,
        Steven Price <steven.price@....com>,
        Thomas Huth <thuth@...hat.com>, Will Deacon <will@...nel.org>,
        Zenghui Yu <yuzenghui@...wei.com>, linux-coco@...ts.linux.dev,
        kvmarm@...ts.cs.columbia.edu, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [RFC kvmtool 19/31] arm64: Don't try to set PSTATE for VCPUs belonging to a realm

From: Christoffer Dall <christoffer.dall@....com>

RME doesn't allow setting the PSTATE but resets it to an architectural
value, and KVM also does not allow setting this register from user
space, so stop trying to do that.

Signed-off-by: Christoffer Dall <christoffer.dall@....com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@....com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 arm/aarch64/kvm-cpu.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arm/aarch64/kvm-cpu.c b/arm/aarch64/kvm-cpu.c
index e7649239..37f9aa9d 100644
--- a/arm/aarch64/kvm-cpu.c
+++ b/arm/aarch64/kvm-cpu.c
@@ -92,11 +92,13 @@ static void reset_vcpu_aarch64(struct kvm_cpu *vcpu)
 
 	reg.addr = (u64)&data;
 
-	/* pstate = all interrupts masked */
-	data	= PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | PSR_MODE_EL1h;
-	reg.id	= ARM64_CORE_REG(regs.pstate);
-	if (ioctl(vcpu->vcpu_fd, KVM_SET_ONE_REG, &reg) < 0)
-		die_perror("KVM_SET_ONE_REG failed (spsr[EL1])");
+	if (!kvm->cfg.arch.is_realm) {
+		/* pstate = all interrupts masked */
+		data	= PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | PSR_MODE_EL1h;
+		reg.id	= ARM64_CORE_REG(regs.pstate);
+		if (ioctl(vcpu->vcpu_fd, KVM_SET_ONE_REG, &reg) < 0)
+			die_perror("KVM_SET_ONE_REG failed (PSTATE)");
+	}
 
 	/* x1...x3 = 0 */
 	data	= 0;
-- 
2.34.1