From: Quentin Perret <qperret@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org, android-kvm@google.com,
linux-kernel@vger.kernel.org, kernel-team@android.com,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
Fuad Tabba <tabba@google.com>,
Mark Rutland <mark.rutland@arm.com>,
David Brazdil <dbrazdil@google.com>
Subject: [RFC PATCH v2 07/26] KVM: arm64: Introduce a BSS section for use at Hyp
Date: Fri, 8 Jan 2021 12:15:05 +0000 [thread overview]
Message-ID: <20210108121524.656872-8-qperret@google.com> (raw)
In-Reply-To: <20210108121524.656872-1-qperret@google.com>
Currently, the hyp code cannot make full use of a bss, as the kernel
section is mapped read-only.
While this mapping could simply be changed to read-write, it would
intermingle even more the hyp and kernel state than they currently are.
Instead, introduce a __hyp_bss section, that uses reserved pages, and
create the appropriate RW hyp mappings during KVM init.
Signed-off-by: Quentin Perret <qperret@google.com>
---
arch/arm64/include/asm/sections.h | 1 +
arch/arm64/kernel/vmlinux.lds.S | 7 +++++++
arch/arm64/kvm/arm.c | 11 +++++++++++
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 8ff579361731..f58cf493de16 100644
--- a/arch/arm64/include/asm/sections.h
+++ b/arch/arm64/include/asm/sections.h
@@ -12,6 +12,7 @@ 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 __hyp_bss_start[], __hyp_bss_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 43af13968dfd..3eca35d5a7cf 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -8,6 +8,13 @@
#define RO_EXCEPTION_TABLE_ALIGN 8
#define RUNTIME_DISCARD_EXIT
+#define BSS_FIRST_SECTIONS \
+ . = ALIGN(PAGE_SIZE); \
+ __hyp_bss_start = .; \
+ *(.hyp.bss) \
+ . = ALIGN(PAGE_SIZE); \
+ __hyp_bss_end = .;
+
#include <asm-generic/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/hyp_image.h>
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 3ac0f3425833..51b53ca36dc5 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1770,7 +1770,18 @@ static int init_hyp_mode(void)
goto out_err;
}
+ /*
+ * .hyp.bss is placed at the beginning of the .bss section, so map that
+ * part RW, and the rest RO as the hyp shouldn't be touching it.
+ */
err = create_hyp_mappings(kvm_ksym_ref(__bss_start),
+ kvm_ksym_ref(__hyp_bss_end), PAGE_HYP);
+ if (err) {
+ kvm_err("Cannot map hyp bss section: %d\n", err);
+ goto out_err;
+ }
+
+ err = create_hyp_mappings(kvm_ksym_ref(__hyp_bss_end),
kvm_ksym_ref(__bss_stop), PAGE_HYP_RO);
if (err) {
kvm_err("Cannot map bss section\n");
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
index 5d76ff2ba63e..dc281d90063e 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
@@ -17,4 +17,5 @@ SECTIONS {
PERCPU_INPUT(L1_CACHE_BYTES)
}
HYP_SECTION(.data..ro_after_init)
+ HYP_SECTION(.bss)
}
--
2.30.0.284.gd98b1dd5eaa7-goog
next prev parent reply other threads:[~2021-01-08 12:17 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 12:14 [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host Quentin Perret
2021-01-08 12:14 ` [RFC PATCH v2 01/26] arm64: lib: Annotate {clear,copy}_page() as position-independent Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 02/26] KVM: arm64: Link position-independent string routines into .hyp.text Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 03/26] arm64: kvm: Add standalone ticket spinlock implementation for use at hyp Quentin Perret
2021-02-01 17:28 ` Will Deacon
2021-02-01 17:40 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 04/26] KVM: arm64: Initialize kvm_nvhe_init_params early Quentin Perret
2021-02-01 17:41 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 05/26] KVM: arm64: Avoid free_page() in page-table allocator Quentin Perret
2021-02-01 17:46 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 06/26] KVM: arm64: Factor memory allocation out of pgtable.c Quentin Perret
2021-02-01 18:16 ` Will Deacon
2021-02-01 18:32 ` Quentin Perret
2021-02-01 18:39 ` Will Deacon
2021-01-08 12:15 ` Quentin Perret [this message]
2021-02-01 18:32 ` [RFC PATCH v2 07/26] KVM: arm64: Introduce a BSS section for use at Hyp Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 08/26] KVM: arm64: Make kvm_call_hyp() a function call " Quentin Perret
2021-02-01 18:41 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 09/26] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code Quentin Perret
2021-02-01 18:43 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 10/26] KVM: arm64: Introduce an early Hyp page allocator Quentin Perret
2021-02-01 19:00 ` Will Deacon
2021-02-02 9:44 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 11/26] KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp Quentin Perret
2021-02-01 19:06 ` Will Deacon
2021-02-02 9:57 ` Quentin Perret
2021-02-02 10:00 ` Will Deacon
2021-02-02 10:14 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 12/26] KVM: arm64: Introduce a Hyp buddy page allocator Quentin Perret
2021-02-02 18:13 ` Will Deacon
2021-02-03 18:33 ` Quentin Perret
2021-02-04 14:31 ` Will Deacon
2021-02-04 14:52 ` Quentin Perret
2021-02-04 17:48 ` Will Deacon
2021-02-04 18:01 ` Quentin Perret
2021-02-04 18:13 ` Will Deacon
2021-02-04 18:24 ` Quentin Perret
2021-02-04 18:19 ` Quentin Perret
2021-02-04 18:24 ` Will Deacon
2021-02-04 18:32 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 13/26] KVM: arm64: Enable access to sanitized CPU features at EL2 Quentin Perret
2021-01-13 11:33 ` Marc Zyngier
2021-01-13 14:23 ` Quentin Perret
2021-01-13 14:35 ` Quentin Perret
2021-01-13 17:27 ` Marc Zyngier
2021-01-13 18:28 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 14/26] KVM: arm64: Factor out vector address calculation Quentin Perret
2021-02-02 18:24 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 15/26] of/fdt: Introduce early_init_dt_add_memory_hyp() Quentin Perret
2021-01-11 14:45 ` Rob Herring
2021-01-12 9:51 ` Quentin Perret
2021-01-12 14:10 ` Rob Herring
2021-01-12 14:26 ` Quentin Perret
2021-01-12 15:53 ` Rob Herring
2021-01-12 16:15 ` Quentin Perret
2021-01-12 16:45 ` Rob Herring
2021-01-12 16:50 ` Quentin Perret
2021-01-15 11:49 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 16/26] KVM: arm64: Prepare Hyp memory protection Quentin Perret
2021-02-03 14:37 ` Will Deacon
2021-02-04 10:47 ` Quentin Perret
2021-02-05 17:56 ` Will Deacon
2021-02-09 10:00 ` Quentin Perret
2021-02-09 12:23 ` Will Deacon
2021-02-19 18:32 ` Sean Christopherson
2021-02-22 11:04 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 17/26] KVM: arm64: Elevate Hyp mappings creation at EL2 Quentin Perret
2021-02-03 15:31 ` Will Deacon
2021-02-04 11:08 ` Quentin Perret
2021-02-05 18:01 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 18/26] KVM: arm64: Use kvm_arch for stage 2 pgtable Quentin Perret
2021-02-03 15:34 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 19/26] KVM: arm64: Use kvm_arch in kvm_s2_mmu Quentin Perret
2021-02-03 15:38 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 20/26] KVM: arm64: Set host stage 2 using kvm_nvhe_init_params Quentin Perret
2021-02-03 16:05 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 21/26] KVM: arm64: Refactor kvm_arm_setup_stage2() Quentin Perret
2021-02-03 15:53 ` Will Deacon
2021-02-04 14:07 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 22/26] KVM: arm64: Refactor __load_guest_stage2() Quentin Perret
2021-02-03 15:54 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 23/26] KVM: arm64: Refactor __populate_fault_info() Quentin Perret
2021-02-03 15:58 ` Will Deacon
2021-02-04 14:18 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 24/26] KVM: arm64: Make memcache anonymous in pgtable allocator Quentin Perret
2021-02-03 15:59 ` Will Deacon
2021-02-04 14:24 ` Quentin Perret
2021-02-04 14:36 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 25/26] KVM: arm64: Reserve memory for host stage 2 Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 26/26] KVM: arm64: Wrap the host with a " Quentin Perret
2021-02-03 16:11 ` Will Deacon
2021-02-04 14:26 ` Quentin Perret
2021-02-04 14:37 ` Will Deacon
2021-02-17 16:27 ` [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host Mate Toth-Pal
2021-02-17 17:24 ` Quentin Perret
2021-02-19 17:54 ` Sean Christopherson
2021-02-19 17:57 ` Quentin Perret
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