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Fuad Tabbaoupton
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KVM: arm64: Handle AIDR_EL1 and REVIDR_EL1 in host for protected VMs
Since commit 17efc1a ("arm64: Expose AIDR_EL1 via sysfs"), AIDR_EL1 is read early during boot. Therefore, a guest running as a protected VM will fail to boot because when it attempts to access AIDR_EL1, access to that register is restricted in pKVM for protected guests. Similar to how MIDR_EL1 is handled by the host for protected VMs, let the host handle accesses to AIDR_EL1 as well as REVIDR_EL1. However note that, unlike MIDR_EL1, AIDR_EL1 and REVIDR_EL1 are trapped by HCR_EL2.TID1. Therefore, explicitly mark them as handled by the host for protected VMs. TID1 is always set in pKVM, because it needs to restrict access to SMIDR_EL1, which is also trapped by that bit. Reported-by: Will Deacon <will@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20250807120133.871892-2-tabba@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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arch/arm64/kvm/hyp/nvhe/sys_regs.c

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@@ -372,6 +372,9 @@ static const struct sys_reg_desc pvm_sys_reg_descs[] = {
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/* Debug and Trace Registers are restricted. */
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/* Group 1 ID registers */
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HOST_HANDLED(SYS_REVIDR_EL1),
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/* AArch64 mappings of the AArch32 ID registers */
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/* CRm=1 */
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AARCH32(SYS_ID_PFR0_EL1),
@@ -460,6 +463,7 @@ static const struct sys_reg_desc pvm_sys_reg_descs[] = {
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HOST_HANDLED(SYS_CCSIDR_EL1),
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HOST_HANDLED(SYS_CLIDR_EL1),
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HOST_HANDLED(SYS_AIDR_EL1),
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HOST_HANDLED(SYS_CSSELR_EL1),
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HOST_HANDLED(SYS_CTR_EL0),
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