diff options
| author | Quentin Perret <qperret@google.com> | 2021-03-19 11:01:15 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-03-19 13:01:20 +0100 |
| commit | 380e18ade4a51334e8806160e6f0fdfaca0b4428 (patch) | |
| tree | fe82cfb30031b7030df54e9fc6360d14fcb32587 /arch/arm64/kvm | |
| parent | KVM: arm64: Factor memory allocation out of pgtable.c (diff) | |
| download | linux-380e18ade4a51334e8806160e6f0fdfaca0b4428.tar.xz linux-380e18ade4a51334e8806160e6f0fdfaca0b4428.zip | |
KVM: arm64: Introduce a BSS section for use at Hyp
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.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-8-qperret@google.com
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/arm.c | 14 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 1 |
2 files changed, 14 insertions, 1 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 2adb8d878bb9..22d6df525254 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1775,7 +1775,19 @@ static int init_hyp_mode(void) goto out_err; } - err = create_hyp_mappings(kvm_ksym_ref(__bss_start), + /* + * .hyp.bss is guaranteed to be placed at the beginning of the .bss + * section thanks to an assertion in the linker script. Map it RW and + * the rest of .bss RO. + */ + err = create_hyp_mappings(kvm_ksym_ref(__hyp_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 cd119d82d8e3..f4562f417d3f 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S @@ -25,4 +25,5 @@ SECTIONS { BEGIN_HYP_SECTION(.data..percpu) PERCPU_INPUT(L1_CACHE_BYTES) END_HYP_SECTION + HYP_SECTION(.bss) } |