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From: David Brazdil <dbrazdil@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: Mark Rutland <mark.rutland@arm.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	kernel-team@android.com, Jonathan Corbet <corbet@lwn.net>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Sudeep Holla <sudeep.holla@arm.com>,
	James Morse <james.morse@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Marc Zyngier <maz@kernel.org>, Tejun Heo <tj@kernel.org>,
	Dennis Zhou <dennis@kernel.org>, Christoph Lameter <cl@linux.com>,
	David Brazdil <dbrazdil@google.com>,
	Will Deacon <will@kernel.org>,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH v4 12/26] kvm: arm64: Add .hyp.data..ro_after_init ELF section
Date: Wed,  2 Dec 2020 18:41:08 +0000	[thread overview]
Message-ID: <20201202184122.26046-13-dbrazdil@google.com> (raw)
In-Reply-To: <20201202184122.26046-1-dbrazdil@google.com>

Add rules for renaming the .data..ro_after_init ELF section in KVM nVHE
object files to .hyp.data..ro_after_init, linking it into the kernel
and mapping it in hyp at runtime.

The section is RW to the host, then mapped RO in hyp. The expectation is
that the host populates the variables in the section and they are never
changed by hyp afterwards.

Signed-off-by: David Brazdil <dbrazdil@google.com>
---
 arch/arm64/include/asm/sections.h |  1 +
 arch/arm64/kernel/vmlinux.lds.S   | 10 ++++++++++
 arch/arm64/kvm/arm.c              |  8 ++++++++
 arch/arm64/kvm/hyp/nvhe/hyp.lds.S |  1 +
 4 files changed, 20 insertions(+)

diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
index 3994169985ef..8ff579361731 100644
--- a/arch/arm64/include/asm/sections.h
+++ b/arch/arm64/include/asm/sections.h
@@ -11,6 +11,7 @@ extern char __alt_instructions[], __alt_instructions_end[];
 extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[];
 extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
 extern char __hyp_text_start[], __hyp_text_end[];
+extern char __hyp_data_ro_after_init_start[], __hyp_data_ro_after_init_end[];
 extern char __idmap_text_start[], __idmap_text_end[];
 extern char __initdata_begin[], __initdata_end[];
 extern char __inittext_begin[], __inittext_end[];
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 1bda604f4c70..4382b5d0645d 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -30,6 +30,13 @@ jiffies = jiffies_64;
 	*(__kvm_ex_table)					\
 	__stop___kvm_ex_table = .;
 
+#define HYPERVISOR_DATA_SECTIONS				\
+	HYP_SECTION_NAME(.data..ro_after_init) : {		\
+		__hyp_data_ro_after_init_start = .;		\
+		*(HYP_SECTION_NAME(.data..ro_after_init))	\
+		__hyp_data_ro_after_init_end = .;		\
+	}
+
 #define HYPERVISOR_PERCPU_SECTION				\
 	. = ALIGN(PAGE_SIZE);					\
 	HYP_SECTION_NAME(.data..percpu) : {			\
@@ -37,6 +44,7 @@ jiffies = jiffies_64;
 	}
 #else /* CONFIG_KVM */
 #define HYPERVISOR_EXTABLE
+#define HYPERVISOR_DATA_SECTIONS
 #define HYPERVISOR_PERCPU_SECTION
 #endif
 
@@ -234,6 +242,8 @@ SECTIONS
 	_sdata = .;
 	RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)
 
+	HYPERVISOR_DATA_SECTIONS
+
 	/*
 	 * Data written with the MMU off but read with the MMU on requires
 	 * cache lines to be invalidated, discarding up to a Cache Writeback
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 6c8594378865..40857cbed3d1 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1705,6 +1705,14 @@ static int init_hyp_mode(void)
 		goto out_err;
 	}
 
+	err = create_hyp_mappings(kvm_ksym_ref(__hyp_data_ro_after_init_start),
+				  kvm_ksym_ref(__hyp_data_ro_after_init_end),
+				  PAGE_HYP_RO);
+	if (err) {
+		kvm_err("Cannot map .hyp.data..ro_after_init section\n");
+		goto out_err;
+	}
+
 	err = create_hyp_mappings(kvm_ksym_ref(__start_rodata),
 				  kvm_ksym_ref(__end_rodata), PAGE_HYP_RO);
 	if (err) {
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
index bb2d986ff696..5d76ff2ba63e 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
@@ -16,4 +16,5 @@ SECTIONS {
 	HYP_SECTION_NAME(.data..percpu) : {
 		PERCPU_INPUT(L1_CACHE_BYTES)
 	}
+	HYP_SECTION(.data..ro_after_init)
 }
-- 
2.29.2.454.gaff20da3a2-goog


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  parent reply	other threads:[~2020-12-02 18:44 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-02 18:40 [PATCH v4 00/26] Opt-in always-on nVHE hypervisor David Brazdil
2020-12-02 18:40 ` [PATCH v4 01/26] kvm: arm64: Add kvm-arm.mode early kernel parameter David Brazdil
2020-12-02 18:40 ` [PATCH v4 02/26] kvm: arm64: Add ARM64_KVM_PROTECTED_MODE CPU capability David Brazdil
2020-12-02 18:40 ` [PATCH v4 03/26] psci: Support psci_ops.get_version for v0.1 David Brazdil
2020-12-02 18:41 ` [PATCH v4 04/26] psci: Split functions to v0.1 and v0.2+ variants David Brazdil
2020-12-03 10:42   ` Mark Rutland
2020-12-02 18:41 ` [PATCH v4 05/26] psci: Replace psci_function_id array with a struct David Brazdil
2020-12-03 10:43   ` Mark Rutland
2020-12-02 18:41 ` [PATCH v4 06/26] psci: Add accessor for psci_0_1_function_ids David Brazdil
2020-12-03 10:47   ` Mark Rutland
2020-12-03 10:51     ` David Brazdil
2020-12-02 18:41 ` [PATCH v4 07/26] arm64: Make cpu_logical_map() take unsigned int David Brazdil
2020-12-02 18:41 ` [PATCH v4 08/26] arm64: Extract parts of el2_setup into a macro David Brazdil
2020-12-02 18:41 ` [PATCH v4 09/26] kvm: arm64: Remove vector_ptr param of hyp-init David Brazdil
2020-12-02 18:41 ` [PATCH v4 10/26] kvm: arm64: Move hyp-init params to a per-CPU struct David Brazdil
2020-12-02 18:41 ` [PATCH v4 11/26] kvm: arm64: Init MAIR/TCR_EL2 from params struct David Brazdil
2020-12-02 18:41 ` David Brazdil [this message]
2020-12-02 18:41 ` [PATCH v4 13/26] kvm: arm64: Support per_cpu_ptr in nVHE hyp code David Brazdil
2020-12-02 18:41 ` [PATCH v4 14/26] kvm: arm64: Create nVHE copy of cpu_logical_map David Brazdil
2020-12-02 18:41 ` [PATCH v4 15/26] kvm: arm64: Add SMC handler in nVHE EL2 David Brazdil
2020-12-03 13:31   ` Marc Zyngier
2020-12-02 18:41 ` [PATCH v4 16/26] kvm: arm64: Bootstrap PSCI " David Brazdil
2020-12-03 10:55   ` Mark Rutland
2020-12-03 13:46   ` Marc Zyngier
2020-12-02 18:41 ` [PATCH v4 17/26] kvm: arm64: Add offset for hyp VA <-> PA conversion David Brazdil
2020-12-07 22:29   ` Qian Cai
2020-12-08 10:08     ` David Brazdil
2020-12-02 18:41 ` [PATCH v4 18/26] kvm: arm64: Forward safe PSCI SMCs coming from host David Brazdil
2020-12-02 18:41 ` [PATCH v4 19/26] kvm: arm64: Extract __do_hyp_init into a helper function David Brazdil
2020-12-02 18:41 ` [PATCH v4 20/26] kvm: arm64: Add function to enter host from KVM nVHE hyp code David Brazdil
2020-12-02 18:41 ` [PATCH v4 21/26] kvm: arm64: Intercept host's CPU_ON SMCs David Brazdil
2020-12-02 18:41 ` [PATCH v4 22/26] kvm: arm64: Intercept host's CPU_SUSPEND PSCI SMCs David Brazdil
2020-12-02 18:41 ` [PATCH v4 23/26] kvm: arm64: Intercept host's SYSTEM_SUSPEND " David Brazdil
2020-12-02 18:41 ` [PATCH v4 24/26] kvm: arm64: Keep nVHE EL2 vector installed David Brazdil
2020-12-02 18:41 ` [PATCH v4 25/26] kvm: arm64: Trap host SMCs in protected mode David Brazdil
2020-12-02 18:41 ` [PATCH v4 26/26] kvm: arm64: Fix EL2 mode availability checks David Brazdil
2020-12-03 19:23 ` [PATCH v4 00/26] Opt-in always-on nVHE hypervisor Marc Zyngier
2020-12-08 19:14   ` David Brazdil
2020-12-08 20:12     ` Marc Zyngier

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