On Fri, Dec 04, 2020 at 06:01:52PM +0000, Quentin Perret wrote:

On Thursday 03 Dec 2020 at 12:57:33 (+0000), Fuad Tabba wrote:
<snip>

quoted

quoted

+int hyp_create_idmap(void);
+int hyp_map_vectors(void);
+int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
+int hyp_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
+int hyp_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
+int __hyp_create_mappings(unsigned long start, unsigned long size,
+                         unsigned long phys, unsigned long prot);
+unsigned long __hyp_create_private_mapping(phys_addr_t phys, size_t size,
+                                          unsigned long prot);
+

nit: I also thought that the hyp_create_mappings function names are a
bit confusing, since there's the create_hyp_mappings functions which
use the aforementioned *hyp_pgtable.

Sure, happy to re-name those (and hyp_pgtable above). Any suggestions?


<snip>

quoted

quoted

+SYM_FUNC_START(__kvm_init_switch_pgd)
+       /* Turn the MMU off */
+       pre_disable_mmu_workaround
+       mrs     x2, sctlr_el2
+       bic     x3, x2, #SCTLR_ELx_M
+       msr     sctlr_el2, x3
+       isb
+
+       tlbi    alle2
+
+       /* Install the new pgtables */
+       ldr     x3, [x0, #NVHE_INIT_PGD_PA]
+       phys_to_ttbr x4, x3
+alternative_if ARM64_HAS_CNP
+       orr     x4, x4, #TTBR_CNP_BIT
+alternative_else_nop_endif
+       msr     ttbr0_el2, x4
+
+       /* Set the new stack pointer */
+       ldr     x0, [x0, #NVHE_INIT_STACK_HYP_VA]
+       mov     sp, x0
+
+       /* And turn the MMU back on! */
+       dsb     nsh
+       isb
+       msr     sctlr_el2, x2
+       isb
+       ret     x1
+SYM_FUNC_END(__kvm_init_switch_pgd)
+

Should the instruction cache be flushed here (ic iallu), to discard
speculatively fetched instructions?

Hmm, Will? Thoughts?

The I-cache is physically tagged, so not sure what invalidation would
achieve here. Fuad -- what do you think could go wrong specifically?

Will