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| author | Will Deacon <will@kernel.org> | 2026-03-30 17:48:11 +0300 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2026-03-30 18:58:07 +0300 |
| commit | 73c55be08932a348f8b0a44f561c33eaa2cf1ad2 (patch) | |
| tree | 25397c0eab7748c6c7abb6831ebfa45ce8fb3563 | |
| parent | f0877a1455cc6a93be14e4da741ce26ac0d6ca6d (diff) | |
| download | linux-73c55be08932a348f8b0a44f561c33eaa2cf1ad2.tar.xz | |
KVM: arm64: Ignore -EAGAIN when mapping in pages for the pKVM host
If the host takes a stage-2 translation fault on two CPUs at the same
time, one of them will get back -EAGAIN from the page-table mapping code
when it runs into the mapping installed by the other.
Rather than handle this explicitly in handle_host_mem_abort(), pass the
new KVM_PGTABLE_WALK_IGNORE_EAGAIN flag to kvm_pgtable_stage2_map() from
__host_stage2_idmap() and return -EEXIST if host_stage2_adjust_range()
finds a valid pte. This will avoid having to test for -EAGAIN on the
reclaim path in subsequent patches.
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-11-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/mem_protect.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index d815265bd374..7d22893ab1dc 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -461,8 +461,15 @@ static bool range_is_memory(u64 start, u64 end) static inline int __host_stage2_idmap(u64 start, u64 end, enum kvm_pgtable_prot prot) { + /* + * We don't make permission changes to the host idmap after + * initialisation, so we can squash -EAGAIN to save callers + * having to treat it like success in the case that they try to + * map something that is already mapped. + */ return kvm_pgtable_stage2_map(&host_mmu.pgt, start, end - start, start, - prot, &host_s2_pool, 0); + prot, &host_s2_pool, + KVM_PGTABLE_WALK_IGNORE_EAGAIN); } /* @@ -504,7 +511,7 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range) return ret; if (kvm_pte_valid(pte)) - return -EAGAIN; + return -EEXIST; if (pte) { WARN_ON(addr_is_memory(addr) && @@ -609,7 +616,6 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) { struct kvm_vcpu_fault_info fault; u64 esr, addr; - int ret = 0; esr = read_sysreg_el2(SYS_ESR); if (!__get_fault_info(esr, &fault)) { @@ -628,8 +634,13 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) BUG_ON(!(fault.hpfar_el2 & HPFAR_EL2_NS)); addr = FIELD_GET(HPFAR_EL2_FIPA, fault.hpfar_el2) << 12; - ret = host_stage2_idmap(addr); - BUG_ON(ret && ret != -EAGAIN); + switch (host_stage2_idmap(addr)) { + case -EEXIST: + case 0: + break; + default: + BUG(); + } } struct check_walk_data { |