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KVM: arm64: Stop save/restoring ACTLR_EL1 

KVM sets HCR_EL2.TACR via HCR_GUEST_FLAGS. This means ACTLR* accesses
from the guest are always trapped, and always return the value in the
sys_regs array.

The guest can't change the value of these registers, so we are
save restoring the reset value, which came from the host.

Stop save/restoring this register. Keep the storage for this register
in sys_regs[] as this is how the value is exposed to user-space,
removing it would break migration.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200529150656.7339-4-james.morse@arm.com
This commit is contained in:
James Morse 2020-05-29 15:06:56 +00:00 committed by Marc Zyngier
parent ef5a294be8
commit e8679fedd0
2 changed files with 0 additions and 4 deletions
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2
arch/arm64/kvm/hyp/sysreg-sr.c
View File

@ -39,7 +39,6 @@ static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
ctxt->sys_regs[SCTLR_EL1] = read_sysreg_el1(SYS_SCTLR);
ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
ctxt->sys_regs[CPACR_EL1] = read_sysreg_el1(SYS_CPACR);
ctxt->sys_regs[TTBR0_EL1] = read_sysreg_el1(SYS_TTBR0);
ctxt->sys_regs[TTBR1_EL1] = read_sysreg_el1(SYS_TTBR1);
@ -122,7 +121,6 @@ static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
isb();
}
write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
write_sysreg_el1(ctxt->sys_regs[CPACR_EL1], SYS_CPACR);
write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1], SYS_TTBR0);
write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1], SYS_TTBR1);

2
arch/arm64/kvm/sys_regs.c
View File

@ -78,7 +78,6 @@ static bool __vcpu_read_sys_reg_from_cpu(int reg, u64 *val)
switch (reg) {
case CSSELR_EL1: *val = read_sysreg_s(SYS_CSSELR_EL1); break;
case SCTLR_EL1: *val = read_sysreg_s(SYS_SCTLR_EL12); break;
case ACTLR_EL1: *val = read_sysreg_s(SYS_ACTLR_EL1); break;
case CPACR_EL1: *val = read_sysreg_s(SYS_CPACR_EL12); break;
case TTBR0_EL1: *val = read_sysreg_s(SYS_TTBR0_EL12); break;
case TTBR1_EL1: *val = read_sysreg_s(SYS_TTBR1_EL12); break;
@ -118,7 +117,6 @@ static bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
switch (reg) {
case CSSELR_EL1: write_sysreg_s(val, SYS_CSSELR_EL1); break;
case SCTLR_EL1: write_sysreg_s(val, SYS_SCTLR_EL12); break;
case ACTLR_EL1: write_sysreg_s(val, SYS_ACTLR_EL1); break;
case CPACR_EL1: write_sysreg_s(val, SYS_CPACR_EL12); break;
case TTBR0_EL1: write_sysreg_s(val, SYS_TTBR0_EL12); break;
case TTBR1_EL1: write_sysreg_s(val, SYS_TTBR1_EL12); break;