From: Quentin Perret <qperret@google.com>
To: catalin.marinas@arm.com, will@kernel.org, maz@kernel.org,
james.morse@arm.com, julien.thierry.kdev@gmail.com,
suzuki.poulose@arm.com
Cc: android-kvm@google.com, linux-kernel@vger.kernel.org,
kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, tabba@google.com,
mark.rutland@arm.com, dbrazdil@google.com,
mate.toth-pal@arm.com, seanjc@google.com, qperret@google.com,
robh+dt@kernel.org
Subject: [PATCH v3 26/32] KVM: arm64: Introduce PROT_NONE mappings for stage 2
Date: Tue, 2 Mar 2021 14:59:56 +0000 [thread overview]
Message-ID: <20210302150002.3685113-27-qperret@google.com> (raw)
In-Reply-To: <20210302150002.3685113-1-qperret@google.com>
Once we start unmapping portions of memory from the host stage 2 (such
as e.g. the hypervisor memory sections, or pages that belong to
protected guests), we will need a way to track page ownership. And
given that all mappings in the host stage 2 will be identity-mapped, we
can use the host stage 2 page-table itself as a simplistic rmap.
As a first step towards this, introduce a new protection attribute
in the stage 2 page table code, called KVM_PGTABLE_PROT_NONE, which
allows to annotate portions of the IPA space as inaccessible. For
simplicity, PROT_NONE mappings are created as invalid mappings with a
software bit set.
Signed-off-by: Quentin Perret <qperret@google.com>
---
arch/arm64/include/asm/kvm_pgtable.h | 2 ++
arch/arm64/kvm/hyp/pgtable.c | 26 ++++++++++++++++++++++++--
2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 9935dbae2cc1..c9f6ed76e0ad 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -80,6 +80,7 @@ struct kvm_pgtable {
* @KVM_PGTABLE_PROT_W: Write permission.
* @KVM_PGTABLE_PROT_R: Read permission.
* @KVM_PGTABLE_PROT_DEVICE: Device attributes.
+ * @KVM_PGTABLE_PROT_NONE: No permission.
*/
enum kvm_pgtable_prot {
KVM_PGTABLE_PROT_X = BIT(0),
@@ -87,6 +88,7 @@ enum kvm_pgtable_prot {
KVM_PGTABLE_PROT_R = BIT(2),
KVM_PGTABLE_PROT_DEVICE = BIT(3),
+ KVM_PGTABLE_PROT_NONE = BIT(4),
};
#define PAGE_HYP (KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W)
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index bdd6e3d4eeb6..8e7059fcfd40 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -48,6 +48,8 @@
KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \
KVM_PTE_LEAF_ATTR_HI_S2_XN)
+#define KVM_PTE_LEAF_SW_BIT_PROT_NONE BIT(55)
+
struct kvm_pgtable_walk_data {
struct kvm_pgtable *pgt;
struct kvm_pgtable_walker *walker;
@@ -120,6 +122,16 @@ static bool kvm_pte_valid(kvm_pte_t pte)
return pte & KVM_PTE_VALID;
}
+static bool kvm_pte_prot_none(kvm_pte_t pte)
+{
+ return pte & KVM_PTE_LEAF_SW_BIT_PROT_NONE;
+}
+
+static inline bool stage2_is_permanent_mapping(kvm_pte_t pte)
+{
+ return kvm_pte_prot_none(pte);
+}
+
static bool kvm_pte_table(kvm_pte_t pte, u32 level)
{
if (level == KVM_PGTABLE_MAX_LEVELS - 1)
@@ -182,7 +194,8 @@ static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level)
pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI);
pte |= FIELD_PREP(KVM_PTE_TYPE, type);
- pte |= KVM_PTE_VALID;
+ if (!kvm_pte_prot_none(pte))
+ pte |= KVM_PTE_VALID;
return pte;
}
@@ -317,7 +330,7 @@ static int hyp_map_set_prot_attr(enum kvm_pgtable_prot prot,
u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW :
KVM_PTE_LEAF_ATTR_LO_S1_AP_RO;
- if (!(prot & KVM_PGTABLE_PROT_R))
+ if (!(prot & KVM_PGTABLE_PROT_R) || (prot & KVM_PGTABLE_PROT_NONE))
return -EINVAL;
if (prot & KVM_PGTABLE_PROT_X) {
@@ -489,6 +502,13 @@ static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
PAGE_S2_MEMATTR(NORMAL);
u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS;
+ if (prot & KVM_PGTABLE_PROT_NONE) {
+ if (prot != KVM_PGTABLE_PROT_NONE)
+ return -EINVAL;
+ attr |= KVM_PTE_LEAF_SW_BIT_PROT_NONE;
+ goto out;
+ }
+
if (!(prot & KVM_PGTABLE_PROT_X))
attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
else if (device)
@@ -502,6 +522,8 @@ static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF;
+
+out:
data->attr = attr;
return 0;
}
--
2.30.1.766.gb4fecdf3b7-goog
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next prev parent reply other threads:[~2021-03-03 16:08 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 14:59 [PATCH v3 00/32] KVM: arm64: A stage 2 for the host Quentin Perret
2021-03-02 14:59 ` [PATCH v3 01/32] arm64: lib: Annotate {clear, copy}_page() as position-independent Quentin Perret
2021-03-02 14:59 ` [PATCH v3 02/32] KVM: arm64: Link position-independent string routines into .hyp.text Quentin Perret
2021-03-02 14:59 ` [PATCH v3 03/32] arm64: kvm: Add standalone ticket spinlock implementation for use at hyp Quentin Perret
2021-03-02 14:59 ` [PATCH v3 04/32] KVM: arm64: Initialize kvm_nvhe_init_params early Quentin Perret
2021-03-04 13:39 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 05/32] KVM: arm64: Avoid free_page() in page-table allocator Quentin Perret
2021-03-02 14:59 ` [PATCH v3 06/32] KVM: arm64: Factor memory allocation out of pgtable.c Quentin Perret
2021-03-04 14:06 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 07/32] KVM: arm64: Introduce a BSS section for use at Hyp Quentin Perret
2021-03-04 14:09 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 08/32] KVM: arm64: Make kvm_call_hyp() a function call " Quentin Perret
2021-03-02 14:59 ` [PATCH v3 09/32] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code Quentin Perret
2021-03-02 14:59 ` [PATCH v3 10/32] KVM: arm64: Introduce an early Hyp page allocator Quentin Perret
2021-03-04 14:38 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 11/32] KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp Quentin Perret
2021-03-02 14:59 ` [PATCH v3 12/32] KVM: arm64: Introduce a Hyp buddy page allocator Quentin Perret
2021-03-04 15:30 ` Will Deacon
2021-03-04 15:49 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 13/32] KVM: arm64: Enable access to sanitized CPU features at EL2 Quentin Perret
2021-03-02 14:59 ` [PATCH v3 14/32] KVM: arm64: Factor out vector address calculation Quentin Perret
2021-03-02 14:59 ` [PATCH v3 15/32] KVM: arm64: Prepare the creation of s1 mappings at EL2 Quentin Perret
2021-03-04 18:47 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 16/32] KVM: arm64: Elevate hypervisor mappings creation " Quentin Perret
2021-03-04 19:25 ` Will Deacon
2021-03-05 9:14 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 17/32] KVM: arm64: Use kvm_arch for stage 2 pgtable Quentin Perret
2021-03-02 14:59 ` [PATCH v3 18/32] KVM: arm64: Use kvm_arch in kvm_s2_mmu Quentin Perret
2021-03-02 14:59 ` [PATCH v3 19/32] KVM: arm64: Set host stage 2 using kvm_nvhe_init_params Quentin Perret
2021-03-02 14:59 ` [PATCH v3 20/32] KVM: arm64: Refactor kvm_arm_setup_stage2() Quentin Perret
2021-03-04 19:35 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 21/32] KVM: arm64: Refactor __load_guest_stage2() Quentin Perret
2021-03-02 14:59 ` [PATCH v3 22/32] KVM: arm64: Refactor __populate_fault_info() Quentin Perret
2021-03-04 19:39 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 23/32] KVM: arm64: Make memcache anonymous in pgtable allocator Quentin Perret
2021-03-04 19:44 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 24/32] KVM: arm64: Reserve memory for host stage 2 Quentin Perret
2021-03-04 19:49 ` Will Deacon
2021-03-05 9:17 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 25/32] KVM: arm64: Sort the hypervisor memblocks Quentin Perret
2021-03-04 19:51 ` Will Deacon
2021-03-02 14:59 ` Quentin Perret [this message]
2021-03-04 20:00 ` [PATCH v3 26/32] KVM: arm64: Introduce PROT_NONE mappings for stage 2 Will Deacon
2021-03-05 9:52 ` Quentin Perret
2021-03-05 19:03 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 27/32] KVM: arm64: Refactor stage2_map_set_prot_attr() Quentin Perret
2021-03-04 20:03 ` Will Deacon
2021-03-05 9:18 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 28/32] KVM: arm64: Add kvm_pgtable_stage2_idmap_greedy() Quentin Perret
2021-03-05 14:39 ` Will Deacon
2021-03-05 15:03 ` Quentin Perret
2021-03-05 16:59 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 29/32] KVM: arm64: Wrap the host with a stage 2 Quentin Perret
2021-03-05 19:29 ` Will Deacon
2021-03-08 9:22 ` Quentin Perret
2021-03-08 12:46 ` Will Deacon
2021-03-08 13:38 ` Quentin Perret
2021-03-08 13:52 ` Will Deacon
2021-03-02 15:00 ` [PATCH v3 30/32] KVM: arm64: Page-align the .hyp sections Quentin Perret
2021-03-04 20:05 ` Will Deacon
2021-03-02 15:00 ` [PATCH v3 31/32] KVM: arm64: Disable PMU support in protected mode Quentin Perret
2021-03-05 19:02 ` Will Deacon
2021-03-02 15:00 ` [PATCH v3 32/32] KVM: arm64: Protect the .hyp sections from the host Quentin Perret
2021-03-05 19:13 ` Will Deacon
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