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AJvYcCUvGtJxkoPnW2C4Kd9rEwLz1RVsK6iR1aGKes9l5omdoTQj7ywJjRxogvD+2ppK+Af7+Z1W55QsroyWtR+ZIt8G@lists.infradead.org X-Gm-Message-State: AOJu0Yw0Lt816rpe+hNT5wImlzijWQ6Hx0hlWji//9e3JO1YOHes4NHh Zx5+C+EyqZVX5ShQgkoAoNDHXk0QY2b0PFN15C0TWEZzI5hrvSIRi0rbeI16bN6U1x1km+KZZfH DSkEHfQ== X-Google-Smtp-Source: AGHT+IEuPMCv7YqXJlNHwKccMEWSYS/+UUaEr2aDY+SyLUIdyjbcKQ2U586hKi+BCjLaIqvUPKXUd5QYm4sG X-Received: from edax2.prod.google.com ([2002:a05:6402:4142:b0:5dc:110c:e5e2]) (user=qperret job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:2546:b0:5d9:f21a:aa26 with SMTP id 4fb4d7f45d1cf-5de450a9e4cmr3320543a12.24.1738940083729; Fri, 07 Feb 2025 06:54:43 -0800 (PST) Date: Fri, 7 Feb 2025 14:54:37 +0000 In-Reply-To: <20250207145438.1333475-1-qperret@google.com> Mime-Version: 1.0 References: <20250207145438.1333475-1-qperret@google.com> X-Mailer: git-send-email 2.48.1.502.g6dc24dfdaf-goog Message-ID: <20250207145438.1333475-2-qperret@google.com> Subject: [PATCH 1/2] KVM: arm64: Improve error handling from check_host_shared_guest() From: Quentin Perret To: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon Cc: Fuad Tabba , Vincent Donnefort , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250207_065446_065091_B172ADC5 X-CRM114-Status: GOOD ( 11.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The check_host_shared_guest() path expects to find a last-level valid PTE in the guest's stage-2 page-table. However, it checks the PTE's level before its validity, which makes it hard for callers to figure out what went wrong. To make error handling simpler, check the PTE's validity first. Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 7ad7b133b81a..41847c04b270 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -943,10 +943,10 @@ static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ip ret = kvm_pgtable_get_leaf(&vm->pgt, ipa, &pte, &level); if (ret) return ret; - if (level != KVM_PGTABLE_LAST_LEVEL) - return -E2BIG; if (!kvm_pte_valid(pte)) return -ENOENT; + if (level != KVM_PGTABLE_LAST_LEVEL) + return -E2BIG; state = guest_get_page_state(pte, ipa); if (state != PKVM_PAGE_SHARED_BORROWED)