Re: [PATCH 12/14] KVM: arm64: Refactor pkvm_pgtable locking
From: Fuad Tabba <hidden>
Date: 2021-07-21 08:42:31
Also in:
kvmarm, lkml
Hi Quentin, On Mon, Jul 19, 2021 at 11:48 AM Quentin Perret [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Refactor the hypervisor stage-1 locking in nVHE protected mode to expose a new pkvm_create_mappings_locked() function. This will be used in later patches to allow walking and changing the hypervisor stage-1 without releasing the lock. Signed-off-by: Quentin Perret <redacted> --- arch/arm64/kvm/hyp/include/nvhe/mm.h | 1 + arch/arm64/kvm/hyp/nvhe/mm.c | 16 ++++++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-)diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h index 8ec3a5a7744b..c76d7136ed9b 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mm.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h@@ -23,6 +23,7 @@ int hyp_map_vectors(void); int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back); 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); int __pkvm_create_mappings(unsigned long start, unsigned long size, unsigned long phys, enum kvm_pgtable_prot prot); unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
The locking logic seems to be consistent, with pkvm_create_mappings() holding the lock for the whole duration of the operation rather than per-iteration. It would be nice though to document which lock should be held for the _locked versions. Thanks, /fuad
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c index a8efdf0f9003..dde22e2a322a 100644 --- a/arch/arm64/kvm/hyp/nvhe/mm.c +++ b/arch/arm64/kvm/hyp/nvhe/mm.c@@ -67,7 +67,7 @@ unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size, return addr; } -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 start = (unsigned long)from; unsigned long end = (unsigned long)to;@@ -81,7 +81,8 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot) int err; phys = hyp_virt_to_phys((void *)virt_addr); - err = __pkvm_create_mappings(virt_addr, PAGE_SIZE, phys, prot); + err = kvm_pgtable_hyp_map(&pkvm_pgtable, virt_addr, PAGE_SIZE, + phys, prot); if (err) return err; }@@ -89,6 +90,17 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot) return 0; } +int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot) +{ + int ret; + + hyp_spin_lock(&pkvm_pgd_lock); + ret = pkvm_create_mappings_locked(from, to, prot); + hyp_spin_unlock(&pkvm_pgd_lock); + + return ret; +} + int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back) { unsigned long start, end; --2.32.0.402.g57bb445576-goog
_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel