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From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: Steven Price <steven.price@arm.com>,
	kvm@vger.kernel.org, kvmarm@lists.linux.dev
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
	James Morse <james.morse@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Zenghui Yu <yuzenghui@huawei.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Joey Gouly <joey.gouly@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Fuad Tabba <tabba@google.com>,
	linux-coco@lists.linux.dev,
	Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Subject: Re: [PATCH v2 07/43] arm64: RME: Check for RME support at KVM init
Date: Tue, 16 Apr 2024 14:30:04 +0100	[thread overview]
Message-ID: <37fa1ff5-9e94-4def-afd6-fb9ea9356977@arm.com> (raw)
In-Reply-To: <20240412084309.1733783-8-steven.price@arm.com>

Hi Steven

On 12/04/2024 09:42, Steven Price wrote:
> Query the RMI version number and check if it is a compatible version. A
> static key is also provided to signal that a supported RMM is available.
> 
> Functions are provided to query if a VM or VCPU is a realm (or rec)
> which currently will always return false.
> 
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
>   arch/arm64/include/asm/kvm_emulate.h | 18 +++++++++
>   arch/arm64/include/asm/kvm_host.h    |  4 ++
>   arch/arm64/include/asm/kvm_rme.h     | 56 ++++++++++++++++++++++++++++
>   arch/arm64/include/asm/virt.h        |  1 +
>   arch/arm64/kvm/Makefile              |  3 +-
>   arch/arm64/kvm/arm.c                 |  9 +++++
>   arch/arm64/kvm/rme.c                 | 52 ++++++++++++++++++++++++++
>   7 files changed, 142 insertions(+), 1 deletion(-)
>   create mode 100644 arch/arm64/include/asm/kvm_rme.h
>   create mode 100644 arch/arm64/kvm/rme.c
> 
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 975af30af31f..6f08398537e2 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -611,4 +611,22 @@ static __always_inline void kvm_reset_cptr_el2(struct kvm_vcpu *vcpu)
>   
>   	kvm_write_cptr_el2(val);
>   }
> +
> +static inline bool kvm_is_realm(struct kvm *kvm)
> +{
> +	if (static_branch_unlikely(&kvm_rme_is_available))
> +		return kvm->arch.is_realm;
> +	return false;
> +}
> +
> +static inline enum realm_state kvm_realm_state(struct kvm *kvm)
> +{
> +	return READ_ONCE(kvm->arch.realm.state);
> +}
> +
> +static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
> +{
> +	return false;
> +}
> +
>   #endif /* __ARM64_KVM_EMULATE_H__ */
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 9e8a496fb284..63b68b85db3f 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -27,6 +27,7 @@
>   #include <asm/fpsimd.h>
>   #include <asm/kvm.h>
>   #include <asm/kvm_asm.h>
> +#include <asm/kvm_rme.h>
>   #include <asm/vncr_mapping.h>
>   
>   #define __KVM_HAVE_ARCH_INTC_INITIALIZED
> @@ -348,6 +349,9 @@ struct kvm_arch {
>   	 * the associated pKVM instance in the hypervisor.
>   	 */
>   	struct kvm_protected_vm pkvm;
> +
> +	bool is_realm;
> +	struct realm realm;
>   };
>   
>   struct kvm_vcpu_fault_info {
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> new file mode 100644
> index 000000000000..922da3f47227
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -0,0 +1,56 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2023 ARM Ltd.
> + */
> +
> +#ifndef __ASM_KVM_RME_H
> +#define __ASM_KVM_RME_H
> +
> +/**
> + * enum realm_state - State of a Realm
> + */
> +enum realm_state {
> +	/**
> +	 * @REALM_STATE_NONE:
> +	 *      Realm has not yet been created. rmi_realm_create() may be
> +	 *      called to create the realm.
> +	 */
> +	REALM_STATE_NONE,
> +	/**
> +	 * @REALM_STATE_NEW:
> +	 *      Realm is under construction, not eligible for execution. Pages
> +	 *      may be populated with rmi_data_create().
> +	 */
> +	REALM_STATE_NEW,
> +	/**
> +	 * @REALM_STATE_ACTIVE:
> +	 *      Realm has been created and is eligible for execution with
> +	 *      rmi_rec_enter(). Pages may no longer be populated with
> +	 *      rmi_data_create().
> +	 */
> +	REALM_STATE_ACTIVE,
> +	/**
> +	 * @REALM_STATE_DYING:
> +	 *      Realm is in the process of being destroyed or has already been
> +	 *      destroyed.
> +	 */
> +	REALM_STATE_DYING,
> +	/**
> +	 * @REALM_STATE_DEAD:
> +	 *      Realm has been destroyed.
> +	 */
> +	REALM_STATE_DEAD
> +};
> +
> +/**
> + * struct realm - Additional per VM data for a Realm
> + *
> + * @state: The lifetime state machine for the realm
> + */
> +struct realm {
> +	enum realm_state state;
> +};
> +
> +int kvm_init_rme(void);
> +
> +#endif
> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
> index 261d6e9df2e1..12cf36c38189 100644
> --- a/arch/arm64/include/asm/virt.h
> +++ b/arch/arm64/include/asm/virt.h
> @@ -81,6 +81,7 @@ void __hyp_reset_vectors(void);
>   bool is_kvm_arm_initialised(void);
>   
>   DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
> +DECLARE_STATIC_KEY_FALSE(kvm_rme_is_available);
>   
>   /* Reports the availability of HYP mode */
>   static inline bool is_hyp_mode_available(void)
> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
> index c0c050e53157..1c1d8cdf381f 100644
> --- a/arch/arm64/kvm/Makefile
> +++ b/arch/arm64/kvm/Makefile
> @@ -20,7 +20,8 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
>   	 vgic/vgic-v3.o vgic/vgic-v4.o \
>   	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
>   	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
> -	 vgic/vgic-its.o vgic/vgic-debug.o
> +	 vgic/vgic-its.o vgic/vgic-debug.o \
> +	 rme.o
>   
>   kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
>   
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 3dee5490eea9..2056c660c5ee 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -38,6 +38,7 @@
>   #include <asm/kvm_mmu.h>
>   #include <asm/kvm_nested.h>
>   #include <asm/kvm_pkvm.h>
> +#include <asm/kvm_rme.h>
>   #include <asm/kvm_emulate.h>
>   #include <asm/sections.h>
>   
> @@ -47,6 +48,8 @@
>   
>   static enum kvm_mode kvm_mode = KVM_MODE_DEFAULT;
>   
> +DEFINE_STATIC_KEY_FALSE(kvm_rme_is_available);
> +
>   DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
>   
>   DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
> @@ -2562,6 +2565,12 @@ static __init int kvm_arm_init(void)
>   
>   	in_hyp_mode = is_kernel_in_hyp_mode();
>   
> +	if (in_hyp_mode) {
> +		err = kvm_init_rme();
> +		if (err)
> +			return err;
> +	}
> +
>   	if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE) ||
>   	    cpus_have_final_cap(ARM64_WORKAROUND_1508412))
>   		kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \
> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> new file mode 100644
> index 000000000000..3dbbf9d046bf
> --- /dev/null
> +++ b/arch/arm64/kvm/rme.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2023 ARM Ltd.
> + */
> +
> +#include <linux/kvm_host.h>
> +
> +#include <asm/rmi_cmds.h>
> +#include <asm/virt.h>
> +
> +static int rmi_check_version(void)
> +{
> +	struct arm_smccc_res res;
> +	int version_major, version_minor;
> +	unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION,
> +						     RMI_ABI_MINOR_VERSION);
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_VERSION, host_version, &res);
> +
> +	if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
> +		return -ENXIO;
> +
> +	version_major = RMI_ABI_VERSION_GET_MAJOR(res.a1);
> +	version_minor = RMI_ABI_VERSION_GET_MINOR(res.a1);
> +

We don't seem to be using the res.a0 to determin if the RMM supports our
requested version. As per RMM spec, section B4.3.23 :

"
The status code and lower revision output values indicate which of the 
following is true, in order of precedence:
  a) The RMM supports an interface revision which is compatible with the
     requested revision.
      • The status code is RMI_SUCCESS.
      • The lower revision is equal to the requested revision.
  b) The RMM does not support an interface revision which is compatible
     with the requested revision The RMM supports an interface revision
     which is incompatible with and less than the requested revision.
      • The status code is RMI_ERROR_INPUT.
      • The lower revision is the highest interface revision which is
        both less than the requested revision and supported by the RMM.

  c) The RMM does not support an interface revision which is compatible
     with the requested revision The RMM supports an interface revision
     which is incompatible with and greater than the requested revision.
      • The status code is RMI_ERROR_INPUT.
      • The lower revision is equal to the higher revision.

So, we could simply check the res.a0 for RMI_SUCCESS and proceed with
marking RMM available.


> +	if (version_major != RMI_ABI_MAJOR_VERSION) {
> +		kvm_err("Unsupported RMI ABI (v%d.%d) host supports v%d.%d\n",
> +			version_major, version_minor,
> +			RMI_ABI_MAJOR_VERSION,
> +			RMI_ABI_MINOR_VERSION);
> +		return -ENXIO;
> +	}
> +
> +	kvm_info("RMI ABI version %d.%d\n", version_major, version_minor);
> +
> +	return 0;
> +}
> +
> +int kvm_init_rme(void)
> +{
> +	if (PAGE_SIZE != SZ_4K)
> +		/* Only 4k page size on the host is supported */
> +		return 0;
> +
> +	if (rmi_check_version())
> +		/* Continue without realm support */
> +		return 0;
> +
> +	/* Future patch will enable static branch kvm_rme_is_available */
> +
> +	return 0;

Do we ever expect this to fail the kvm initialisation ? Otherwise, we
could leave it as a void ?

Suzuki
> +}


  reply	other threads:[~2024-04-16 13:30 UTC|newest]

Thread overview: 135+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-12  8:40 [v2] Support for Arm CCA VMs on Linux Steven Price
2024-04-11 18:54 ` Itaru Kitayama
2024-04-15  8:14   ` Steven Price
2024-06-01 20:40     ` Jason Gunthorpe
2024-04-12  8:41 ` [PATCH v2 00/14] arm64: Support for running as a guest in Arm CCA Steven Price
2024-04-12  8:42   ` [PATCH v2 01/14] arm64: rsi: Add RSI definitions Steven Price
2024-04-12  8:42   ` [PATCH v2 02/14] arm64: Detect if in a realm and set RIPAS RAM Steven Price
2024-05-10 17:35     ` Catalin Marinas
2024-05-14 10:18       ` Suzuki K Poulose
2024-05-16 14:32         ` Catalin Marinas
2024-05-15 15:03       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 03/14] arm64: realm: Query IPA size from the RMM Steven Price
2024-05-13 14:03     ` Catalin Marinas
2024-05-16 15:13       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 04/14] arm64: Mark all I/O as non-secure shared Steven Price
2024-04-12  8:42   ` [PATCH v2 05/14] fixmap: Allow architecture overriding set_fixmap_io Steven Price
2024-04-12  8:42   ` [PATCH v2 06/14] arm64: Override set_fixmap_io Steven Price
2024-05-13 16:14     ` Catalin Marinas
2024-05-14 10:21       ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 07/14] arm64: Make the PHYS_MASK_SHIFT dynamic Steven Price
2024-05-13 16:38     ` Catalin Marinas
2024-05-16 15:34       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 08/14] arm64: Enforce bounce buffers for realm DMA Steven Price
2024-05-13 16:56     ` Catalin Marinas
2024-04-12  8:42   ` [PATCH v2 09/14] arm64: Enable memory encrypt for Realms Steven Price
2024-04-15  3:13     ` kernel test robot
2024-04-25 13:42       ` Suzuki K Poulose
2024-04-25 15:52         ` Steven Price
2024-04-25 16:29         ` Suzuki K Poulose
2024-04-25 18:16           ` Emanuele Rocca
2024-05-14 18:00     ` Catalin Marinas
2024-05-15 10:47       ` Suzuki K Poulose
2024-05-16  7:48         ` Catalin Marinas
2024-05-16  9:06           ` Suzuki K Poulose
2024-05-20 16:53         ` Catalin Marinas
2024-05-20 20:32           ` Michael Kelley
2024-05-21 10:14             ` Catalin Marinas
2024-05-21 15:58               ` Michael Kelley
2024-04-12  8:42   ` [PATCH v2 10/14] arm64: Force device mappings to be non-secure shared Steven Price
2024-05-15  9:01     ` Catalin Marinas
2024-05-15 11:00       ` Suzuki K Poulose
2024-05-17  9:34         ` Catalin Marinas
2024-04-12  8:42   ` [PATCH v2 11/14] efi: arm64: Map Device with Prot Shared Steven Price
2024-04-12  8:42   ` [PATCH v2 12/14] arm64: realm: Support nonsecure ITS emulation shared Steven Price
2024-05-15 11:01     ` Catalin Marinas
2024-05-22 15:52       ` Steven Price
2024-05-22 17:05         ` Catalin Marinas
2024-05-23  9:57           ` Steven Price
2024-04-12  8:42   ` [PATCH v2 13/14] arm64: rsi: Interfaces to query attestation token Steven Price
2024-05-15 11:10     ` Catalin Marinas
2024-05-22 15:52       ` Steven Price
2024-05-31 16:29         ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 14/14] virt: arm-cca-guest: TSM_REPORT support for realms Steven Price
2024-04-24 13:06     ` Thomas Fossati
2024-04-24 13:27       ` Suzuki K Poulose
2024-04-24 13:19     ` Suzuki K Poulose
2024-04-12  8:42 ` [PATCH v2 00/43] arm64: Support for Arm CCA in KVM Steven Price
2024-04-12  8:42   ` [PATCH v2 01/43] KVM: Prepare for handling only shared mappings in mmu_notifier events Steven Price
2024-04-25  9:48     ` Fuad Tabba
2024-04-25 15:58       ` Steven Price
2024-04-25 22:56         ` Sean Christopherson
2024-04-12  8:42   ` [PATCH v2 02/43] kvm: arm64: pgtable: Track the number of pages in the entry level Steven Price
2024-04-12  8:42   ` [PATCH v2 03/43] kvm: arm64: Include kvm_emulate.h in kvm/arm_psci.h Steven Price
2024-04-12  8:42   ` [PATCH v2 04/43] arm64: RME: Handle Granule Protection Faults (GPFs) Steven Price
2024-04-16 11:17     ` Suzuki K Poulose
2024-04-18 13:17       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 05/43] arm64: RME: Add SMC definitions for calling the RMM Steven Price
2024-04-16 12:38     ` Suzuki K Poulose
2024-04-18 13:17       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 06/43] arm64: RME: Add wrappers for RMI calls Steven Price
2024-04-16 13:14     ` Suzuki K Poulose
2024-04-19 11:18       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 07/43] arm64: RME: Check for RME support at KVM init Steven Price
2024-04-16 13:30     ` Suzuki K Poulose [this message]
2024-04-22 15:39       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 08/43] arm64: RME: Define the user ABI Steven Price
2024-04-12  8:42   ` [PATCH v2 09/43] arm64: RME: ioctls to create and configure realms Steven Price
2024-04-17  9:51     ` Suzuki K Poulose
2024-04-22 16:33       ` Steven Price
2024-04-18 16:04     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 10/43] kvm: arm64: Expose debug HW register numbers for Realm Steven Price
2024-04-12  8:42   ` [PATCH v2 11/43] arm64: kvm: Allow passing machine type in KVM creation Steven Price
2024-04-17 10:20     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 12/43] arm64: RME: Keep a spare page delegated to the RMM Steven Price
2024-04-17 10:19     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 13/43] arm64: RME: RTT handling Steven Price
2024-04-17 13:37     ` Suzuki K Poulose
2024-04-24 10:59       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 14/43] arm64: RME: Allocate/free RECs to match vCPUs Steven Price
2024-04-18  9:23     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 15/43] arm64: RME: Support for the VGIC in realms Steven Price
2024-04-12  8:42   ` [PATCH v2 16/43] KVM: arm64: Support timers in realm RECs Steven Price
2024-04-18  9:30     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 17/43] arm64: RME: Allow VMM to set RIPAS Steven Price
2024-04-19  9:34     ` Suzuki K Poulose
2024-04-19 10:20       ` Suzuki K Poulose
2024-05-01 15:47       ` Steven Price
2024-05-02 10:16         ` Suzuki K Poulose
2024-04-25  9:53     ` Fuad Tabba
2024-05-01 14:27     ` Jean-Philippe Brucker
2024-05-01 14:56       ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 18/43] arm64: RME: Handle realm enter/exit Steven Price
2024-04-19 13:00     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 19/43] KVM: arm64: Handle realm MMIO emulation Steven Price
2024-04-12  8:42   ` [PATCH v2 20/43] arm64: RME: Allow populating initial contents Steven Price
2024-04-19 13:17     ` Suzuki K Poulose
2024-04-12  8:42   ` [PATCH v2 21/43] arm64: RME: Runtime faulting of memory Steven Price
2024-04-25 10:43     ` Fuad Tabba
2024-05-31 16:03       ` Steven Price
2024-04-12  8:42   ` [PATCH v2 22/43] KVM: arm64: Handle realm VCPU load Steven Price
2024-04-12  8:42   ` [PATCH v2 23/43] KVM: arm64: Validate register access for a Realm VM Steven Price
2024-04-12  8:42   ` [PATCH v2 24/43] KVM: arm64: Handle Realm PSCI requests Steven Price
2024-04-12  8:42   ` [PATCH v2 25/43] KVM: arm64: WARN on injected undef exceptions Steven Price
2024-04-12  8:42   ` [PATCH v2 26/43] arm64: Don't expose stolen time for realm guests Steven Price
2024-04-12  8:42   ` [PATCH v2 27/43] arm64: rme: allow userspace to inject aborts Steven Price
2024-04-12  8:42   ` [PATCH v2 28/43] arm64: rme: support RSI_HOST_CALL Steven Price
2024-04-12  8:42   ` [PATCH v2 29/43] arm64: rme: Allow checking SVE on VM instance Steven Price
2024-04-12  8:42   ` [PATCH v2 30/43] arm64: RME: Always use 4k pages for realms Steven Price
2024-04-12  8:42   ` [PATCH v2 31/43] arm64: rme: Prevent Device mappings for Realms Steven Price
2024-04-12  8:42   ` [PATCH v2 32/43] arm_pmu: Provide a mechanism for disabling the physical IRQ Steven Price
2024-04-12  8:42   ` [PATCH v2 33/43] arm64: rme: Enable PMU support with a realm guest Steven Price
2024-04-13 23:44     ` kernel test robot
2024-04-18 16:06       ` Suzuki K Poulose
2024-04-12  8:43   ` [PATCH v2 34/43] kvm: rme: Hide KVM_CAP_READONLY_MEM for realm guests Steven Price
2024-04-12  8:43   ` [PATCH v2 35/43] arm64: RME: Propagate number of breakpoints and watchpoints to userspace Steven Price
2024-04-12  8:43   ` [PATCH v2 36/43] arm64: RME: Set breakpoint parameters through SET_ONE_REG Steven Price
2024-04-12  8:43   ` [PATCH v2 37/43] arm64: RME: Initialize PMCR.N with number counter supported by RMM Steven Price
2024-04-12  8:43   ` [PATCH v2 38/43] arm64: RME: Propagate max SVE vector length from RMM Steven Price
2024-04-12  8:43   ` [PATCH v2 39/43] arm64: RME: Configure max SVE vector length for a Realm Steven Price
2024-04-12  8:43   ` [PATCH v2 40/43] arm64: RME: Provide register list for unfinalized RME RECs Steven Price
2024-04-12  8:43   ` [PATCH v2 41/43] arm64: RME: Provide accurate register list Steven Price
2024-04-12  8:43   ` [PATCH v2 42/43] arm64: kvm: Expose support for private memory Steven Price
2024-04-25 14:44     ` Fuad Tabba
2024-04-12  8:43   ` [PATCH v2 43/43] KVM: arm64: Allow activating realms Steven Price
2024-04-12 16:52 ` [v2] Support for Arm CCA VMs on Linux Jean-Philippe Brucker

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    --in-reply-to=37fa1ff5-9e94-4def-afd6-fb9ea9356977@arm.com \
    --to=suzuki.poulose@arm.com \
    --cc=alexandru.elisei@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=christoffer.dall@arm.com \
    --cc=gankulkarni@os.amperecomputing.com \
    --cc=james.morse@arm.com \
    --cc=joey.gouly@arm.com \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.linux.dev \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-coco@lists.linux.dev \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=oliver.upton@linux.dev \
    --cc=steven.price@arm.com \
    --cc=tabba@google.com \
    --cc=will@kernel.org \
    --cc=yuzenghui@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

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