[PATCH v3 03/66] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

Marc Zyngier
2020-12-10T16:01:45Z

From: Christoffer Dall <christoffer.dall@arm.com>

Reset the VCPU with PSTATE.M = EL2h when the nested virtualization
feature is enabled on the VCPU.

Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
[maz: rework register reset not to use empty data structures]
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/reset.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 47f3f035f3ea..2d2c780e6c69 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -27,6 +27,7 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
#include <asm/virt.h>

/* Maximum phys_shift supported for any VM on this host */
@@ -38,6 +39,9 @@ static u32 kvm_ipa_limit;
#define VCPU_RESET_PSTATE_EL1 (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
PSR_F_BIT | PSR_D_BIT)

+#define VCPU_RESET_PSTATE_EL2 (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \
+ PSR_F_BIT | PSR_D_BIT)
+
#define VCPU_RESET_PSTATE_SVC (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
PSR_AA32_I_BIT | PSR_AA32_F_BIT)

@@ -224,11 +228,18 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
switch (vcpu->arch.target) {
default:
if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
- if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1)) {
+ /*
+ * The CPU must support 32bit EL1, and 32bit
+ * NV is just not a thing...
+ */
+ if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1) ||
+ nested_virt_in_use(vcpu)) {
ret = -EINVAL;
goto out;
}
pstate = VCPU_RESET_PSTATE_SVC;
+ } else if (nested_virt_in_use(vcpu)) {
+ pstate = VCPU_RESET_PSTATE_EL2;
} else {
pstate = VCPU_RESET_PSTATE_EL1;
}
--
2.29.2