[PATCH v6 03/64] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

Marc Zyngier
2022-01-28T12:21:05Z

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

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

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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 | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index ecc40c8cd6f6..d19a9aad2d85 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)

@@ -188,12 +192,19 @@ static bool vcpu_allowed_register_width(struct kvm_vcpu *vcpu)
unsigned long i;

is32bit = vcpu_has_feature(vcpu, KVM_ARM_VCPU_EL1_32BIT);
- if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1) && is32bit)
- return false;
+ if (is32bit) {
+ /* The HW must obviously support AArch32 at EL1 */
+ if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1))
+ return false;

- /* MTE is incompatible with AArch32 */
- if (kvm_has_mte(vcpu->kvm) && is32bit)
- return false;
+ /* MTE is incompatible with AArch32 */
+ if (kvm_has_mte(vcpu->kvm))
+ return false;
+
+ /* NV is incompatible with AArch32 */
+ if (vcpu_has_nv(vcpu))
+ return false;
+ }

/* Check that the vcpus are either all 32bit or all 64bit */
kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
@@ -265,10 +276,18 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
goto out;
}

+ if (vcpu_has_nv(vcpu) &&
+ vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
switch (vcpu->arch.target) {
default:
if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
pstate = VCPU_RESET_PSTATE_SVC;
+ } else if (vcpu_has_nv(vcpu)) {
+ pstate = VCPU_RESET_PSTATE_EL2;
} else {
pstate = VCPU_RESET_PSTATE_EL1;
}