diff mbox series

[v3] powerpc/XIVE: SVM: share the event-queue page with the Hypervisor.

Message ID 20200426020518.GC5853@oc0525413822.ibm.com
State Superseded
Headers show
Series [v3] powerpc/XIVE: SVM: share the event-queue page with the Hypervisor. | expand

Commit Message

Ram Pai April 26, 2020, 2:05 a.m. UTC 
From 10ea2eaf492ca3f22f67a5a63a2b7865e45299ad Mon Sep 17 00:00:00 2001
From: Ram Pai <linuxram@us.ibm.com>
Date: Mon, 24 Feb 2020 01:09:48 -0500
Subject: [PATCH v3] powerpc/XIVE: SVM: share the event-queue page with the
 Hypervisor.

XIVE interrupt controller uses an Event Queue (EQ) to enqueue event
notifications when an exception occurs. The EQ is a single memory page
provided by the O/S defining a circular buffer, one per server and
priority couple.

On baremetal, the EQ page is configured with an OPAL call. On pseries,
an extra hop is necessary and the guest OS uses the hcall
H_INT_SET_QUEUE_CONFIG to configure the XIVE interrupt controller.

The XIVE controller being Hypervisor privileged, it will not be allowed
to enqueue event notifications for a Secure VM unless the EQ pages are
shared by the Secure VM.

Hypervisor/Ultravisor still requires support for the TIMA and ESB page
fault handlers. Until this is complete, QEMU can use the emulated XIVE
device for Secure VMs, option "kernel_irqchip=off" on the QEMU pseries
machine.

Cc: kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Michael Anderson <andmike@linux.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cedric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>

v3: fix a minor semantics in description.
    and added reviewed-by from Cedric and Greg.
v2: better description of the patch from Cedric.
---
 arch/powerpc/sysdev/xive/spapr.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Michael Ellerman June 9, 2020, 5:29 a.m. UTC | #1 
On Sat, 25 Apr 2020 19:05:18 -0700, Ram Pai wrote:
> >From 10ea2eaf492ca3f22f67a5a63a2b7865e45299ad Mon Sep 17 00:00:00 2001
> From: Ram Pai <linuxram@us.ibm.com>
> Date: Mon, 24 Feb 2020 01:09:48 -0500
> Subject: [PATCH v3] powerpc/XIVE: SVM: share the event-queue page with the
>  Hypervisor.
> 
> XIVE interrupt controller uses an Event Queue (EQ) to enqueue event
> notifications when an exception occurs. The EQ is a single memory page
> provided by the O/S defining a circular buffer, one per server and
> priority couple.
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc/xive: Share the event-queue page with the Hypervisor.
      https://git.kernel.org/powerpc/c/094235222d41d68d35de18170058d94a96a82628

cheers
diff mbox series

Patch

diff --git a/arch/powerpc/sysdev/xive/spapr.c b/arch/powerpc/sysdev/xive/spapr.c
index 55dc61c..608b52f 100644
--- a/arch/powerpc/sysdev/xive/spapr.c
+++ b/arch/powerpc/sysdev/xive/spapr.c
@@ -26,6 +26,8 @@ 
 #include <asm/xive.h>
 #include <asm/xive-regs.h>
 #include <asm/hvcall.h>
+#include <asm/svm.h>
+#include <asm/ultravisor.h>
 
 #include "xive-internal.h"
 
@@ -501,6 +503,9 @@  static int xive_spapr_configure_queue(u32 target, struct xive_q *q, u8 prio,
 		rc = -EIO;
 	} else {
 		q->qpage = qpage;
+		if (is_secure_guest())
+			uv_share_page(PHYS_PFN(qpage_phys),
+					1 << xive_alloc_order(order));
 	}
 fail:
 	return rc;
@@ -534,6 +539,8 @@  static void xive_spapr_cleanup_queue(unsigned int cpu, struct xive_cpu *xc,
 		       hw_cpu, prio);
 
 	alloc_order = xive_alloc_order(xive_queue_shift);
+	if (is_secure_guest())
+		uv_unshare_page(PHYS_PFN(__pa(q->qpage)), 1 << alloc_order);
 	free_pages((unsigned long)q->qpage, alloc_order);
 	q->qpage = NULL;
 }