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From: Steven Price <steven.price@arm.com>
To: kvm@vger.kernel.org, kvmarm@lists.linux.dev
Cc: Steven Price <steven.price@arm.com>,
	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>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	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: [PATCH v2 12/43] arm64: RME: Keep a spare page delegated to the RMM
Date: Fri, 12 Apr 2024 09:42:38 +0100	[thread overview]
Message-ID: <20240412084309.1733783-13-steven.price@arm.com> (raw)
In-Reply-To: <20240412084309.1733783-1-steven.price@arm.com>

Pages can only be populated/destroyed on the RMM at the 4KB granule,
this requires creating the full depth of RTTs. However if the pages are
going to be combined into a 4MB huge page the last RTT is only
temporarily needed. Similarly when freeing memory the huge page must be
temporarily split requiring temporary usage of the full depth oF RTTs.

To avoid needing to perform a temporary allocation and delegation of a
page for this purpose we keep a spare delegated page around. In
particular this avoids the need for memory allocation while destroying
the realm guest.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_rme.h | 5 +++++
 arch/arm64/kvm/rme.c             | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index cf8cc4d30364..fba85e9ce3ae 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -50,6 +50,9 @@ enum realm_state {
  * @state: The lifetime state machine for the realm
  * @rd: Kernel mapping of the Realm Descriptor (RD)
  * @params: Parameters for the RMI_REALM_CREATE command
+ * @spare_page: A physical page that has been delegated to the Realm world but
+ *              is otherwise free. Used to avoid temporary allocation during
+ *              RTT operations.
  * @num_aux: The number of auxiliary pages required by the RMM
  * @vmid: VMID to be used by the RMM for the realm
  * @ia_bits: Number of valid Input Address bits in the IPA
@@ -60,6 +63,8 @@ struct realm {
 	void *rd;
 	struct realm_params *params;
 
+	phys_addr_t spare_page;
+
 	unsigned long num_aux;
 	unsigned int vmid;
 	unsigned int ia_bits;
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 658d14e8d87d..9652ec6ab2fd 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -103,6 +103,7 @@ static int realm_create_rd(struct kvm *kvm)
 	}
 
 	realm->rd = rd;
+	realm->spare_page = PHYS_ADDR_MAX;
 
 	if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) {
 		WARN_ON(rmi_realm_destroy(rd_phys));
@@ -283,6 +284,13 @@ void kvm_destroy_realm(struct kvm *kvm)
 
 	rme_vmid_release(realm->vmid);
 
+	if (realm->spare_page != PHYS_ADDR_MAX) {
+		/* Leak the page if the undelegate fails */
+		if (!WARN_ON(rmi_granule_undelegate(realm->spare_page)))
+			free_page((unsigned long)phys_to_virt(realm->spare_page));
+		realm->spare_page = PHYS_ADDR_MAX;
+	}
+
 	for (i = 0; i < pgt->pgd_pages; i++) {
 		phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
 
-- 
2.34.1


  parent reply	other threads:[~2024-04-12  8:43 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
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   ` Steven Price [this message]
2024-04-17 10:19     ` [PATCH v2 12/43] arm64: RME: Keep a spare page delegated to the RMM 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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