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powerpc/pseries/svm: Allow IOMMU to work in SVM

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H_PUT_TCE_INDIRECT uses a shared page to send up to 512 TCE to
a hypervisor in a single hypercall. This does not work for secure VMs
as the page needs to be shared or the VM should use H_PUT_TCE instead.

This disables H_PUT_TCE_INDIRECT by clearing the FW_FEATURE_PUT_TCE_IND
feature bit so SVMs will map TCEs using H_PUT_TCE.

This is not a part of init_svm() as it is called too late after FW
patching is done and may result in a warning like this:

[    3.727716] Firmware features changed after feature patching!
[    3.727965] WARNING: CPU: 0 PID: 1 at (...)arch/powerpc/lib/feature-fixups.c:466 check_features+0xa4/0xc0

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191216041924.42318-5-aik@ozlabs.ru
This commit is contained in:
Alexey Kardashevskiy 2019-12-16 15:19:24 +11:00 committed by Michael Ellerman
parent 17a0364cb0
commit 978bff4e52
1 changed files with 7 additions and 0 deletions
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7
arch/powerpc/platforms/pseries/firmware.c
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@ -22,6 +22,7 @@
#include <asm/firmware.h>
#include <asm/prom.h>
#include <asm/udbg.h>
#include <asm/svm.h>
#include "pseries.h"
@ -101,6 +102,12 @@ static void __init fw_hypertas_feature_init(const char *hypertas,
}
}
if (is_secure_guest() &&
(powerpc_firmware_features & FW_FEATURE_PUT_TCE_IND)) {
powerpc_firmware_features &= ~FW_FEATURE_PUT_TCE_IND;
pr_debug("SVM: disabling PUT_TCE_IND firmware feature\n");
}
pr_debug(" <- fw_hypertas_feature_init()\n");
}