Merge tag 'kvmarm-fixes-5.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git...

KVM/arm64 fixes for 5.11, take #3

- Avoid clobbering extra registers on initialisation

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 31b060a4404524720cf5ae05f1e21014a35de0c6..b17bf19217f1100b962bb5794c05a9214262cb54 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -47,6 +47,8 @@ __invalid:
        b       .
 
        /*
+        * Only uses x0..x3 so as to not clobber callee-saved SMCCC registers.
+        *
         * x0: SMCCC function ID
         * x1: struct kvm_nvhe_init_params PA
         */
@@ -70,9 +72,9 @@ __do_hyp_init:
        eret
 
 1:     mov     x0, x1
-       mov     x4, lr
-       bl      ___kvm_hyp_init
-       mov     lr, x4
+       mov     x3, lr
+       bl      ___kvm_hyp_init                 // Clobbers x0..x2
+       mov     lr, x3
 
        /* Hello, World! */
        mov     x0, #SMCCC_RET_SUCCESS
@@ -82,8 +84,8 @@ SYM_CODE_END(__kvm_hyp_init)
 /*
  * Initialize the hypervisor in EL2.
  *
- * Only uses x0..x3 so as to not clobber callee-saved SMCCC registers
- * and leave x4 for the caller.
+ * Only uses x0..x2 so as to not clobber callee-saved SMCCC registers
+ * and leave x3 for the caller.
  *
  * x0: struct kvm_nvhe_init_params PA
  */
@@ -112,9 +114,9 @@ alternative_else_nop_endif
        /*
         * Set the PS bits in TCR_EL2.
         */
-       ldr     x1, [x0, #NVHE_INIT_TCR_EL2]
-       tcr_compute_pa_size x1, #TCR_EL2_PS_SHIFT, x2, x3
-       msr     tcr_el2, x1
+       ldr     x0, [x0, #NVHE_INIT_TCR_EL2]
+       tcr_compute_pa_size x0, #TCR_EL2_PS_SHIFT, x1, x2
+       msr     tcr_el2, x0
 
        isb
 
@@ -193,7 +195,7 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu)
 
        /* Enable MMU, set vectors and stack. */
        mov     x0, x28
-       bl      ___kvm_hyp_init                 // Clobbers x0..x3
+       bl      ___kvm_hyp_init                 // Clobbers x0..x2
 
        /* Leave idmap. */
        mov     x0, x29