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KVM: arm64: Fix __pkvm_init_switch_pgd call ABI

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Fix the mismatch between the (incorrect) C signature, C call site, and
asm implementation by aligning all three on an API passing the
parameters (pgd and SP) separately, instead of as a bundled struct.

Remove the now unnecessary memory accesses while the MMU is off from the
asm, which simplifies the C caller (as it does not need to convert a VA
struct pointer to PA) and makes the code slightly more robust by
offsetting the struct fields from C and properly expressing the call to
the C compiler (e.g. type checker and kCFI).

Fixes: f320bc742b ("KVM: arm64: Prepare the creation of s1 mappings at EL2")
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240610063244.2828978-3-ptosi@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Pierre-Clément Tosi
2024-06-10 07:32:31 +01:00
committed by Oliver Upton
parent a8f0655887
commit ea9d7c83d1
3 changed files with 17 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
arch/arm64/include/asm/kvm_hyp.h
View File

@@ -124,8 +124,8 @@ void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
#endif
#ifdef __KVM_NVHE_HYPERVISOR__
void __pkvm_init_switch_pgd(phys_addr_t phys, unsigned long size,
phys_addr_t pgd, void *sp, void *cont_fn);
void __pkvm_init_switch_pgd(phys_addr_t pgd, unsigned long sp,
void (*fn)(void));
int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
unsigned long *per_cpu_base, u32 hyp_va_bits);
void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);

24
arch/arm64/kvm/hyp/nvhe/hyp-init.S
View File

@@ -265,33 +265,35 @@ alternative_else_nop_endif
SYM_CODE_END(__kvm_handle_stub_hvc)
/*
* void __pkvm_init_switch_pgd(phys_addr_t pgd, unsigned long sp,
* void (*fn)(void));
*/
SYM_FUNC_START(__pkvm_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
mrs x3, sctlr_el2
bic x4, x3, #SCTLR_ELx_M
msr sctlr_el2, x4
isb
tlbi alle2
/* Install the new pgtables */
ldr x3, [x0, #NVHE_INIT_PGD_PA]
phys_to_ttbr x4, x3
phys_to_ttbr x5, x0
alternative_if ARM64_HAS_CNP
orr x4, x4, #TTBR_CNP_BIT
orr x5, x5, #TTBR_CNP_BIT
alternative_else_nop_endif
msr ttbr0_el2, x4
msr ttbr0_el2, x5
/* Set the new stack pointer */
ldr x0, [x0, #NVHE_INIT_STACK_HYP_VA]
mov sp, x0
mov sp, x1
/* And turn the MMU back on! */
dsb nsh
isb
set_sctlr_el2 x2
ret x1
set_sctlr_el2 x3
ret x2
SYM_FUNC_END(__pkvm_init_switch_pgd)
.popsection

4
arch/arm64/kvm/hyp/nvhe/setup.c
View File

@@ -339,7 +339,7 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
{
struct kvm_nvhe_init_params *params;
void *virt = hyp_phys_to_virt(phys);
void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
typeof(__pkvm_init_switch_pgd) *fn;
int ret;
BUG_ON(kvm_check_pvm_sysreg_table());
@@ -363,7 +363,7 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
/* Jump in the idmap page to switch to the new page-tables */
params = this_cpu_ptr(&kvm_init_params);
fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
fn(__hyp_pa(params), __pkvm_init_finalise);
fn(params->pgd_pa, params->stack_hyp_va, __pkvm_init_finalise);
unreachable();
}