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AHgh+Rr7UHzMIj/wXhtFXuWbGhYv+mXq4ymq1Pie1VD10Fby4h6kctP9XSNaF3XDob6J3wa3G8ZIgHQ7FPQgcOc=@vger.kernel.org X-Gm-Message-State: AOJu0YwQoESGIbvNv2tRxottGW4casEw08ZJqWsfLI/bzs8Y47e4/5Yb Gp7qIGerzo3UaJG2IyVQzPoPJQ3mR7TOn7NqFgRhQJkxN6tw8u5KoUxTNlYN02BxYlTeR+60Y9J EXISPMBq5BCp0k7+jRey2HXyyvDCciQ== X-Received: from wmbhi12.prod.google.com ([2002:a05:600c:534c:b0:498:124b:1aa0]) (user=sebastianene job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:2e54:b0:495:4e1d:82df with SMTP id 5b1f17b1804b1-4994e7c1445mr233498895e9.10.1786121033123; Fri, 07 Aug 2026 09:43:53 -0700 (PDT) Date: Fri, 7 Aug 2026 16:43:20 +0000 In-Reply-To: <20260807164322.2970811-2-sebastianene@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260807164322.2970811-2-sebastianene@google.com> X-Mailer: git-send-email 2.55.0.654.g21b8a5bc05-goog Message-ID: <20260807164322.2970811-12-sebastianene@google.com> Subject: [PATCH v2 10/13] KVM: arm64: Restrict host updates to GITS_CTLR From: Sebastian Ene To: catalin.marinas@arm.com, fuad.tabba@linux.dev, joey.gouly@arm.com, mark.rutland@arm.com, maz@kernel.org, oupton@kernel.org, rananta@google.com, Sascha.Bischoff@arm.com, suzuki.poulose@arm.com, will@kernel.org Cc: kvmarm@lists.linux.dev, android-kvm@google.com, bgrzesik@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, nathan@kernel.org, perlarsen@google.com, sebastianene@google.com, seiden@linux.ibm.com, smostafa@google.com, tglx@kernel.org, vdonnefort@google.com, vladimir.murzin@arm.com, yuzenghui@huawei.com, zenghui.yu@linux.dev Content-Type: text/plain; charset="UTF-8" Prevent unpredictable hardware behavior when the host tries to enable the ITS while it is not in quiescent state. Signed-off-by: Sebastian Ene --- arch/arm64/kvm/hyp/nvhe/its_emulate.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/its_emulate.c b/arch/arm64/kvm/hyp/nvhe/its_emulate.c index 5629e2a070df..b9b71aa18d48 100644 --- a/arch/arm64/kvm/hyp/nvhe/its_emulate.c +++ b/arch/arm64/kvm/hyp/nvhe/its_emulate.c @@ -403,8 +403,35 @@ static void cwriter_read(struct pkvm_protected_reg *region, u64 offset, u64 *rea *read = readq_relaxed(its->base + GITS_CWRITER); } +static void ctlr_read(struct pkvm_protected_reg *region, u64 offset, u64 *read) +{ + struct its_priv_state *its = region->priv; + *read = readl_relaxed(its->base + GITS_CTLR); +} + +static void ctlr_write(struct pkvm_protected_reg *region, u64 offset, u64 value) +{ + struct its_priv_state *its = region->priv; + bool is_quiescent, is_enabled; + u32 ctlr; + + ctlr = readl_relaxed(its->base + GITS_CTLR); + is_quiescent = !!(ctlr & GITS_CTLR_QUIESCENT); + is_enabled = !!(ctlr & GITS_CTLR_ENABLE); + + /* + * If it's disabled and not in quiescent state and it tries to enable + * it, bail out. + */ + if (!is_enabled && (value & GITS_CTLR_ENABLE) && !is_quiescent) + return; + + writel_relaxed(value, its->base + GITS_CTLR); +} + static struct its_handler its_handlers[] = { ITS_HANDLER(GITS_CWRITER, sizeof(u64), cwriter_write, cwriter_read), + ITS_HANDLER(GITS_CTLR, sizeof(u32), ctlr_write, ctlr_read), {}, }; -- 2.55.0.654.g21b8a5bc05-goog