From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- Documentation/fb/pvr2fb.rst | 66 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 Documentation/fb/pvr2fb.rst (limited to 'Documentation/fb/pvr2fb.rst') diff --git a/Documentation/fb/pvr2fb.rst b/Documentation/fb/pvr2fb.rst new file mode 100644 index 000000000..315ce085a --- /dev/null +++ b/Documentation/fb/pvr2fb.rst @@ -0,0 +1,66 @@ +=============================================== +pvr2fb - PowerVR 2 graphics frame buffer driver +=============================================== + +This is a driver for PowerVR 2 based graphics frame buffers, such as the +one found in the Dreamcast. + +Advantages: + + * It provides a nice large console (128 cols + 48 lines with 1024x768) + without using tiny, unreadable fonts (NOT on the Dreamcast) + * You can run XF86_FBDev on top of /dev/fb0 + * Most important: boot logo :-) + +Disadvantages: + + * Driver is largely untested on non-Dreamcast systems. + +Configuration +============= + +You can pass kernel command line options to pvr2fb with +`video=pvr2fb:option1,option2:value2,option3` (multiple options should be +separated by comma, values are separated from options by `:`). + +Accepted options: + +========== ================================================================== +font:X default font to use. All fonts are supported, including the + SUN12x22 font which is very nice at high resolutions. + + +mode:X default video mode with format [xres]x[yres]-@ + The following video modes are supported: + 640x640-16@60, 640x480-24@60, 640x480-32@60. The Dreamcast + defaults to 640x480-16@60. At the time of writing the + 24bpp and 32bpp modes function poorly. Work to fix that is + ongoing + + Note: the 640x240 mode is currently broken, and should not be + used for any reason. It is only mentioned here as a reference. + +inverse invert colors on screen (for LCD displays) + +nomtrr disables write combining on frame buffer. This slows down driver + but there is reported minor incompatibility between GUS DMA and + XFree under high loads if write combining is enabled (sound + dropouts). MTRR is enabled by default on systems that have it + configured and that support it. + +cable:X cable type. This can be any of the following: vga, rgb, and + composite. If none is specified, we guess. + +output:X output type. This can be any of the following: pal, ntsc, and + vga. If none is specified, we guess. +========== ================================================================== + +X11 +=== + +XF86_FBDev has been shown to work on the Dreamcast in the past - though not yet +on any 2.6 series kernel. + +Paul Mundt + +Updated by Adrian McMenamin -- cgit v1.3.1