KVM: Check KVM_CAP_DIRTY_LOG_{RING, RING_ACQ_REL} prior to enabling them - linux-dev - Linux kernel development work

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author	Gavin Shan <gshan@redhat.com>	2022-10-31 08:36:15 +0800
committer	Marc Zyngier <maz@kernel.org>	2022-10-31 17:22:15 +0000
commit	7a2726ec3290c52f52ce8d5f5af73ab8c7681bc1 (patch)
tree	d95b5cf059814da3a0b2126afb09760505c9ed13 /arch/nds32/boot/git:/ssh:/git@git.zx2c4.com
parent	KVM: arm64: Fix bad dereference on MTE-enabled systems (diff)

KVM: Check KVM_CAP_DIRTY_LOG_{RING, RING_ACQ_REL} prior to enabling them

There are two capabilities related to ring-based dirty page tracking: KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL. Both are supported by x86. However, arm64 supports KVM_CAP_DIRTY_LOG_RING_ACQ_REL only when the feature is supported on arm64. The userspace doesn't have to enable the advertised capability, meaning KVM_CAP_DIRTY_LOG_RING can be enabled on arm64 by userspace and it's wrong. Fix it by double checking if the capability has been advertised prior to enabling it. It's rejected to enable the capability if it hasn't been advertised. Fixes: 17601bfed909 ("KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option") Reported-by: Sean Christopherson <seanjc@google.com> Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221031003621.164306-4-gshan@redhat.com

Diffstat (limited to 'arch/nds32/boot/git:/ssh:/git@git.zx2c4.com')

0 files changed, 0 insertions, 0 deletions

/* * IBM RTAS driver interface to hvc_console.c * * (C) Copyright IBM Corporation 2001-2005 * (C) Copyright Red Hat, Inc. 2005 * * Author(s): Maximino Augilar <IBM STI Design Center> * : Ryan S. Arnold <rsa@us.ibm.com> * : Utz Bacher <utz.bacher@de.ibm.com> * : David Woodhouse <dwmw2@infradead.org> * * inspired by drivers/char/hvc_console.c * written by Anton Blanchard and Paul Mackerras * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/console.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/init.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <asm/irq.h> #include <asm/rtas.h> #include "hvc_console.h" #define hvc_rtas_cookie 0x67781e15 struct hvc_struct *hvc_rtas_dev; static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE; static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE; static inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf, int count) { int i; for (i = 0; i < count; i++) { if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i])) break; } return i; } static int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count) { int i, c; for (i = 0; i < count; i++) { if (rtas_call(rtascons_get_char_token, 0, 2, &c)) break; buf[i] = c; } return i; } static struct hv_ops hvc_rtas_get_put_ops = { .get_chars = hvc_rtas_read_console, .put_chars = hvc_rtas_write_console, }; static int hvc_rtas_init(void) { struct hvc_struct *hp; if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) rtascons_put_char_token = rtas_token("put-term-char"); if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) return -EIO; if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) rtascons_get_char_token = rtas_token("get-term-char"); if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) return -EIO; BUG_ON(hvc_rtas_dev); /* Allocate an hvc_struct for the console device we instantiated * earlier. Save off hp so that we can return it on exit */ hp = hvc_alloc(hvc_rtas_cookie, NO_IRQ, &hvc_rtas_get_put_ops, 16); if (IS_ERR(hp)) return PTR_ERR(hp); hvc_rtas_dev = hp; return 0; } module_init(hvc_rtas_init); /* This will tear down the tty portion of the driver */ static void __exit hvc_rtas_exit(void) { /* Really the fun isn't over until the worker thread breaks down and * the tty cleans up */ if (hvc_rtas_dev) hvc_remove(hvc_rtas_dev); } module_exit(hvc_rtas_exit); /* This will happen prior to module init. There is no tty at this time? */ static int __init hvc_rtas_console_init(void) { rtascons_put_char_token = rtas_token("put-term-char"); if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) return -EIO; rtascons_get_char_token = rtas_token("get-term-char"); if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) return -EIO; hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops); add_preferred_console("hvc", 0, NULL); return 0; } console_initcall(hvc_rtas_console_init);


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