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UPSTREAM: KVM: arm64: Generally disallow SMC64 for AArch32 guests

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The only valid calling SMC calling convention from an AArch32 state is
SMC32. Disallow any PSCI function that sets the SMC64 function ID bit
when called from AArch32 rather than comparing against known SMC64 PSCI
functions.

Note that without this change KVM advertises the SMC64 flavor of
SYSTEM_RESET2 to AArch32 guests.

Bug: 254441685
Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest")
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220322183538.2757758-2-oupton@google.com
(cherry picked from commit 2da0aebc74dba6a09ac90b88e38860fbc65d6c0a)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I1674f3950727b4d572f8d5da463f7eaf22c9efb2
This commit is contained in:
Oliver Upton
2022-03-22 18:35:36 +00:00
committed by Lee Jones
parent 35c5fa9834
commit 46d726e380
1 changed files with 5 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
arch/arm64/kvm/psci.c
View File

@@ -188,15 +188,11 @@ static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
{
switch(fn) {
case PSCI_0_2_FN64_CPU_SUSPEND:
case PSCI_0_2_FN64_CPU_ON:
case PSCI_0_2_FN64_AFFINITY_INFO:
/* Disallow these functions for 32bit guests */
if (vcpu_mode_is_32bit(vcpu))
return PSCI_RET_NOT_SUPPORTED;
break;
}
/*
* Prevent 32 bit guests from calling 64 bit PSCI functions.
*/
if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
return PSCI_RET_NOT_SUPPORTED;
return 0;
}