KVM: arm64: Init MAIR/TCR_EL2 from params struct

MAIR_EL2 and TCR_EL2 are currently initialized from their _EL1 values.
This will not work once KVM starts intercepting PSCI ON/SUSPEND SMCs
and initializing EL2 state before EL1 state.

Obtain the EL1 values during KVM init and store them in the init params
struct. The struct will stay in memory and can be used when booting new
cores.

Take the opportunity to move copying the T0SZ value from idmap_t0sz in
KVM init rather than in .hyp.idmap.text. This avoids the need for the
idmap_t0sz symbol alias.

Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-12-dbrazdil@google.com

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index cb750c5..4e2661d 100644 (file)
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -151,6 +151,8 @@ extern void *__vhe_undefined_symbol;
 #endif
 
 struct kvm_nvhe_init_params {
+       unsigned long mair_el2;
+       unsigned long tcr_el2;
        unsigned long tpidr_el2;
        unsigned long stack_hyp_va;
        phys_addr_t pgd_pa;

diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 52771a4..5e82488 100644 (file)
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -109,6 +109,8 @@ int main(void)
   DEFINE(CPU_APGAKEYLO_EL1,    offsetof(struct kvm_cpu_context, sys_regs[APGAKEYLO_EL1]));
   DEFINE(HOST_CONTEXT_VCPU,    offsetof(struct kvm_cpu_context, __hyp_running_vcpu));
   DEFINE(HOST_DATA_CONTEXT,    offsetof(struct kvm_host_data, host_ctxt));
+  DEFINE(NVHE_INIT_MAIR_EL2,   offsetof(struct kvm_nvhe_init_params, mair_el2));
+  DEFINE(NVHE_INIT_TCR_EL2,    offsetof(struct kvm_nvhe_init_params, tcr_el2));
   DEFINE(NVHE_INIT_TPIDR_EL2,  offsetof(struct kvm_nvhe_init_params, tpidr_el2));
   DEFINE(NVHE_INIT_STACK_HYP_VA,       offsetof(struct kvm_nvhe_init_params, stack_hyp_va));
   DEFINE(NVHE_INIT_PGD_PA,     offsetof(struct kvm_nvhe_init_params, pgd_pa));

diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 4b32588..08e69fa 100644 (file)
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -77,9 +77,6 @@ KVM_NVHE_ALIAS(panic);
 /* Vectors installed by hyp-init on reset HVC. */
 KVM_NVHE_ALIAS(__hyp_stub_vectors);
 
-/* IDMAP TCR_EL1.T0SZ as computed by the EL1 init code */
-KVM_NVHE_ALIAS(idmap_t0sz);
-
 /* Kernel symbol used by icache_is_vpipt(). */
 KVM_NVHE_ALIAS(__icache_flags);
 

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 0b823e4..d9961f0 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1336,6 +1336,7 @@ static void cpu_init_hyp_mode(void)
 {
        struct kvm_nvhe_init_params *params = this_cpu_ptr_nvhe_sym(kvm_init_params);
        struct arm_smccc_res res;
+       unsigned long tcr;
 
        /* Switch from the HYP stub to our own HYP init vector */
        __hyp_set_vectors(kvm_get_idmap_vector());
@@ -1348,6 +1349,27 @@ static void cpu_init_hyp_mode(void)
        params->tpidr_el2 = (unsigned long)this_cpu_ptr_nvhe_sym(__per_cpu_start) -
                            (unsigned long)kvm_ksym_ref(CHOOSE_NVHE_SYM(__per_cpu_start));
 
+       params->mair_el2 = read_sysreg(mair_el1);
+
+       /*
+        * The ID map may be configured to use an extended virtual address
+        * range. This is only the case if system RAM is out of range for the
+        * currently configured page size and VA_BITS, in which case we will
+        * also need the extended virtual range for the HYP ID map, or we won't
+        * be able to enable the EL2 MMU.
+        *
+        * However, at EL2, there is only one TTBR register, and we can't switch
+        * between translation tables *and* update TCR_EL2.T0SZ at the same
+        * time. Bottom line: we need to use the extended range with *both* our
+        * translation tables.
+        *
+        * So use the same T0SZ value we use for the ID map.
+        */
+       tcr = (read_sysreg(tcr_el1) & TCR_EL2_MASK) | TCR_EL2_RES1;
+       tcr &= ~TCR_T0SZ_MASK;
+       tcr |= (idmap_t0sz & GENMASK(TCR_TxSZ_WIDTH - 1, 0)) << TCR_T0SZ_OFFSET;
+       params->tcr_el2 = tcr;
+
        params->stack_hyp_va = kern_hyp_va(__this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE);
        params->pgd_pa = kvm_mmu_get_httbr();
 

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index e712e31..712f572 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -71,48 +71,26 @@ __do_hyp_init:
 1:     ldr     x0, [x1, #NVHE_INIT_TPIDR_EL2]
        msr     tpidr_el2, x0
 
+       ldr     x0, [x1, #NVHE_INIT_MAIR_EL2]
+       msr     mair_el2, x0
+
        ldr     x0, [x1, #NVHE_INIT_STACK_HYP_VA]
        mov     sp, x0
 
-       ldr     x1, [x1, #NVHE_INIT_PGD_PA]
-       phys_to_ttbr x0, x1
+       ldr     x0, [x1, #NVHE_INIT_PGD_PA]
+       phys_to_ttbr x2, x0
 alternative_if ARM64_HAS_CNP
-       orr     x0, x0, #TTBR_CNP_BIT
+       orr     x2, x2, #TTBR_CNP_BIT
 alternative_else_nop_endif
-       msr     ttbr0_el2, x0
-
-       mrs     x0, tcr_el1
-       mov_q   x1, TCR_EL2_MASK
-       and     x0, x0, x1
-       mov     x1, #TCR_EL2_RES1
-       orr     x0, x0, x1
-
-       /*
-        * The ID map may be configured to use an extended virtual address
-        * range. This is only the case if system RAM is out of range for the
-        * currently configured page size and VA_BITS, in which case we will
-        * also need the extended virtual range for the HYP ID map, or we won't
-        * be able to enable the EL2 MMU.
-        *
-        * However, at EL2, there is only one TTBR register, and we can't switch
-        * between translation tables *and* update TCR_EL2.T0SZ at the same
-        * time. Bottom line: we need to use the extended range with *both* our
-        * translation tables.
-        *
-        * So use the same T0SZ value we use for the ID map.
-        */
-       ldr_l   x1, idmap_t0sz
-       bfi     x0, x1, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
+       msr     ttbr0_el2, x2
 
        /*
         * Set the PS bits in TCR_EL2.
         */
+       ldr     x0, [x1, #NVHE_INIT_TCR_EL2]
        tcr_compute_pa_size x0, #TCR_EL2_PS_SHIFT, x1, x2
-
        msr     tcr_el2, x0
 
-       mrs     x0, mair_el1
-       msr     mair_el2, x0
        isb
 
        /* Invalidate the stale TLBs from Bootloader */