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Message-Id: <20220225033548.1912117-3-kaleshsingh@google.com>
Date: Thu, 24 Feb 2022 19:34:47 -0800
From: Kalesh Singh <kaleshsingh@...gle.com>
To: unlisted-recipients:; (no To-header on input)
Cc: will@...nel.org, maz@...nel.org, qperret@...gle.com,
tabba@...gle.com, surenb@...gle.com, kernel-team@...roid.com,
Kalesh Singh <kaleshsingh@...gle.com>,
James Morse <james.morse@....com>,
Alexandru Elisei <alexandru.elisei@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Catalin Marinas <catalin.marinas@....com>,
Mark Rutland <mark.rutland@....com>,
Mark Brown <broonie@...nel.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Peter Collingbourne <pcc@...gle.com>,
"Madhavan T. Venkataraman" <madvenka@...ux.microsoft.com>,
Andrew Scull <ascull@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Ard Biesheuvel <ardb@...nel.org>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
linux-kernel@...r.kernel.org
Subject: [PATCH v4 2/8] KVM: arm64: Introduce pkvm_alloc_private_va_range()
pkvm_hyp_alloc_private_va_range() can be used to reserve private VA ranges
in the pKVM nVHE hypervisor (). Also update __pkvm_create_private_mapping()
to allow specifying an alignment for the private VA mapping.
These will be used to implement stack guard pages for pKVM nVHE hypervisor
(in a subsequent patch in the series).
Credits to Quentin Perret <qperret@...gle.com> for the idea of moving
private VA allocation out of __pkvm_create_private_mapping()
Signed-off-by: Kalesh Singh <kaleshsingh@...gle.com>
---
Changes in v4:
- Handle null ptr in pkvm_alloc_private_va_range() and replace
IS_ERR_OR_NULL checks in callers with IS_ERR checks, per Fuad
- Fix kernel-doc comments format, per Fuad
- Format __pkvm_create_private_mapping() prototype args (< 80 col), per Fuad
Changes in v3:
- Handle null ptr in IS_ERR_OR_NULL checks, per Mark
Changes in v2:
- Allow specifying an alignment for the private VA allocations, per Marc
arch/arm64/kvm/hyp/include/nvhe/mm.h | 3 +-
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 5 ++-
arch/arm64/kvm/hyp/nvhe/mm.c | 60 +++++++++++++++++-----------
arch/arm64/kvm/mmu.c | 2 +-
4 files changed, 43 insertions(+), 27 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h
index 2d08510c6cc1..76d6fcf1d4f4 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h
@@ -20,7 +20,8 @@ int pkvm_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot);
unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
- enum kvm_pgtable_prot prot);
+ size_t align, enum kvm_pgtable_prot prot);
+unsigned long pkvm_alloc_private_va_range(size_t size, size_t align);
static inline void hyp_vmemmap_range(phys_addr_t phys, unsigned long size,
unsigned long *start, unsigned long *end)
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 5e2197db0d32..96b2312a0f1d 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -158,9 +158,10 @@ static void handle___pkvm_create_private_mapping(struct kvm_cpu_context *host_ct
{
DECLARE_REG(phys_addr_t, phys, host_ctxt, 1);
DECLARE_REG(size_t, size, host_ctxt, 2);
- DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 3);
+ DECLARE_REG(size_t, align, host_ctxt, 3);
+ DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 4);
- cpu_reg(host_ctxt, 1) = __pkvm_create_private_mapping(phys, size, prot);
+ cpu_reg(host_ctxt, 1) = __pkvm_create_private_mapping(phys, size, align, prot);
}
static void handle___pkvm_prot_finalize(struct kvm_cpu_context *host_ctxt)
diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c
index 526a7d6fa86f..e6355180aa49 100644
--- a/arch/arm64/kvm/hyp/nvhe/mm.c
+++ b/arch/arm64/kvm/hyp/nvhe/mm.c
@@ -37,38 +37,53 @@ static int __pkvm_create_mappings(unsigned long start, unsigned long size,
return err;
}
-unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
- enum kvm_pgtable_prot prot)
+/**
+ * pkvm_alloc_private_va_range - Allocates a private VA range.
+ * @size: The size of the VA range to reserve.
+ * @align: The required alignment for the allocation.
+ *
+ * The private VA range is allocated above __io_map_base.
+ */
+unsigned long pkvm_alloc_private_va_range(size_t size, size_t align)
{
- unsigned long addr;
- int err;
+ unsigned long base, addr;
hyp_spin_lock(&pkvm_pgd_lock);
- size = PAGE_ALIGN(size + offset_in_page(phys));
- addr = __io_map_base;
- __io_map_base += size;
+ addr = ALIGN(__io_map_base, align);
+
+ /* The allocated size is always a multiple of PAGE_SIZE */
+ base = addr + PAGE_ALIGN(size);
/* Are we overflowing on the vmemmap ? */
- if (__io_map_base > __hyp_vmemmap) {
- __io_map_base -= size;
+ if (!addr || base > __hyp_vmemmap)
addr = (unsigned long)ERR_PTR(-ENOMEM);
- goto out;
- }
-
- err = kvm_pgtable_hyp_map(&pkvm_pgtable, addr, size, phys, prot);
- if (err) {
- addr = (unsigned long)ERR_PTR(err);
- goto out;
- }
+ else
+ __io_map_base = base;
- addr = addr + offset_in_page(phys);
-out:
hyp_spin_unlock(&pkvm_pgd_lock);
return addr;
}
+unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
+ size_t align, enum kvm_pgtable_prot prot)
+{
+ unsigned long addr;
+ int err;
+
+ size += offset_in_page(phys);
+ addr = pkvm_alloc_private_va_range(size, align);
+ if (IS_ERR((void *)addr))
+ return addr;
+
+ err = __pkvm_create_mappings(addr, size, phys, prot);
+ if (err)
+ return (unsigned long)ERR_PTR(err);
+
+ return addr + offset_in_page(phys);
+}
+
int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot)
{
unsigned long start = (unsigned long)from;
@@ -152,10 +167,9 @@ int hyp_map_vectors(void)
return 0;
phys = __hyp_pa(__bp_harden_hyp_vecs);
- bp_base = (void *)__pkvm_create_private_mapping(phys,
- __BP_HARDEN_HYP_VECS_SZ,
- PAGE_HYP_EXEC);
- if (IS_ERR_OR_NULL(bp_base))
+ bp_base = (void *)__pkvm_create_private_mapping(phys, __BP_HARDEN_HYP_VECS_SZ,
+ PAGE_SIZE, PAGE_HYP_EXEC);
+ if (IS_ERR(bp_base))
return PTR_ERR(bp_base);
__hyp_bp_vect_base = bp_base;
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a4868a6fa1c3..433c49766671 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -506,7 +506,7 @@ int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
if (!kvm_host_owns_hyp_mappings()) {
addr = kvm_call_hyp_nvhe(__pkvm_create_private_mapping,
- phys_addr, size, prot);
+ phys_addr, size, align, prot);
if (IS_ERR((void *)addr))
return PTR_ERR((void *)addr);
*haddr = addr;
--
2.35.1.574.g5d30c73bfb-goog
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